Organic compound, light-emitting element, light-emitting device, electronic appliance, and lighting device

ABSTRACT

An organic compound that emits blue light with high color purity and has a long lifetime is provided as a novel substance. The organic compound is a fluorescent organic compound having a structure in which benzonaphthofuranylamine is bonded to the 1-position and the 6-position of a pyrene skeleton.

TECHNICAL FIELD

One embodiment of the present invention relates to a novel organiccompound emitting fluorescence. One embodiment of the present inventionrelates to a light-emitting element, a light-emitting device, anelectronic appliance, and a lighting device each of which uses the novelorganic compound emitting fluorescence.

BACKGROUND ART

Light-emitting elements utilizing electroluminescence (EL) are highlyanticipated as next-generation display technology. In recent years,research and development has been extensively conducted on suchlight-emitting elements. In a basic structure of the light-emittingelement, a layer containing a light-emitting substance is providedbetween a pair of electrodes. By applying voltage to the element, lightemission can be obtained from the light-emitting substance in an excitedstate.

The light-emitting element is a self-luminous element and thus hasadvantages over a liquid crystal display element, such as highvisibility of the pixels and no need for backlight, and is considered tobe suitable as a flat panel display element. Another major advantage ofthe light-emitting element is that it can be fabricated to be thin andlightweight. Besides, very high response speed is also a feature of thelight-emitting element.

Furthermore, the light-emitting element can be formed in a film form,and thus makes it possible to provide planar light emission easily.Thus, a large-area element utilizing planar light emission can beformed. This is a feature that is difficult to obtain with point lightsources typified by an incandescent lamp and an LED or linear lightsources typified by a fluorescent lamp. Thus, the light-emitting elementalso has great potential as a planar light source that can be used for alighting device and the like.

Light-emitting elements are broadly classified according to whether theyuse an organic compound or an inorganic compound as a light-emittingsubstance. In the case where an organic compound is used as alight-emitting substance, by applying voltage to a light-emittingelement, electrons and holes are injected from a pair of electrodes intoa layer including the light-emitting organic compound, whereby currentflows. Then electrons and holes (i.e., carriers) are recombined, so thatthe light-emitting organic compound is excited. The light-emittingorganic compound returns to a ground state from the excited state,thereby emitting light. Note that an excited state of an organiccompound can be of two types: a singlet excited state and a tripletexcited state, and luminescence from the singlet excited state (S*) isreferred to as fluorescence, and luminescence from the triplet excitedstate (T*) is referred to as phosphorescence. Note that in fabricationof a light-emitting element, characteristics of the light-emittingelement are greatly affected by such light-emitting substances.

A method has been disclosed in which a novel fluorescent material withhigh emission efficiency is used for a light-emitting layer included ina light-emitting element to provide a highly efficient light-emittingelement (see, for example, Patent Document 1).

REFERENCE

Patent Document 1: Japanese Published Patent Application No. 2005-75868

DISCLOSURE OF INVENTION

Although novel fluorescent materials with good characteristics have beendeveloped as disclosed in Patent Document 1, development of novelmaterials with better characteristics is demanded.

In view of the above, one embodiment of the present invention provides afluorescent organic compound that emits light with high color purity andhas a long lifetime as a novel substance. One embodiment of the presentinvention also provides a light-emitting element that emits blue lightwith high color purity and has a long lifetime, a light-emitting device,an electronic appliance, or a lighting device.

One embodiment of the present invention is a blue fluorescent organiccompound that has a structure in which benzonaphthofuranylamine isbonded to each of the 1-position and the 6-position of a pyreneskeleton. Thus, one embodiment of the present invention is an organiccompound represented by General Formula (G1).

In the formula, Ar¹ and Ar² separately represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms forming a ring; R¹to R⁸ separately represent hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms,or a substituted or unsubstituted aryl group having 6 to 10 carbonatoms; and X¹ and X² separately represent a substituted or unsubstitutedbenzo[b]naphtho[1,2-d]furanyl group.

It is preferable that each nitrogen atom in General Formula (G1) havingthe above-described structure be bonded to the 6-position or the8-position of the benzo[b]naphtho[1,2-d]furanyl group.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G2).

In the formula, Ar¹ and Ar² separately represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms forming a ring; andR¹ to R¹⁷ and R¹⁹ to R²⁷ separately represent hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 6 carbon atoms, a cyano group,halogen, a substituted or unsubstituted haloalkyl group having 1 to 6carbon atoms, or a substituted or unsubstituted aryl group having 6 to10 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G3).

In the formula, Ar¹ and Ar² separately represent a substituted orunsubstituted aryl group having 6 to 13 carbon atoms foliating a ring;and R¹ to R⁸, R¹⁰ to R¹⁸, and R²⁰ to R²⁸ separately represent hydrogen,a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G4).

In the formula, R¹ to R⁸ and R²⁹ to R³⁸ separately represent hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G5).

In the formula, R¹ to R⁸ and R²⁹ to R³⁸ separately represent hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by Structural Formula (100).

Another embodiment of the present invention is an organic compoundrepresented by Structural Formula (101).

Another embodiment of the present invention is a method for synthesizingeach of the organic compounds represented by General Formulae (G1) to(G5) and 8-halogenated benzo[b]naphtho[1,2-d]furan, a novel organiccompound synthesized using any of the organic compounds represented byGeneral Formulae (G1) to (G5). Note that halogen in 8-halogenatedbenzo[b]naphtho[1,2-d]furan is preferably chlorine, bromine, or iodine.

Another embodiment of the present invention is a light-emitting elementcontaining any of the organic compounds represented by General Formulae(G1) to (G5) and a light-emitting device including the light-emittingelement.

Note that other embodiments of the present invention are not only alight-emitting device including the light-emitting element but also alighting device including the light-emitting device. The light-emittingdevice in this specification refers to an image display device and alight source (e.g., a lighting device). In addition, the light-emittingdevice includes, in its category, all of a module in which alight-emitting device is connected to a connector such as a flexibleprinted circuit (FPC), a tape carrier package (TCP), a module in which aprinted wiring board is provided on the tip of a TCP, and a module inwhich an integrated circuit (IC) is directly mounted on a light-emittingelement by a chip on glass (COG) method.

According to one embodiment of the present invention, a fluorescentorganic compound that emits blue light (emission peak wavelength: around450 nm) with high color purity, has high efficiency, and has a longlifetime can be provided as a novel substance. The use of the organiccompound of one embodiment of the present invention can provide alight-emitting element that emits blue light with high color purity, alight-emitting device, an electronic appliance, or a lighting device. Alight-emitting element, a light-emitting device, an electronicappliance, or a lighting device that has low power consumption and has along lifetime can also be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a structure of a light-emitting element.

FIGS. 2A and 2B each illustrate a structure of a light-emitting element.

FIGS. 3A and 3B illustrate a light-emitting device.

FIGS. 4A to 4D illustrate electronic appliances.

FIG. 5 illustrates lighting devices.

FIGS. 6A and 6B are ¹H NMR charts of an organic compound represented byStructural Formula (100).

FIGS. 7A and 7B show ultraviolet-visible absorption spectra and emissionspectra of the organic compound represented by Structural Formula (100).

FIGS. 8A and 8B are ¹H NMR charts of an organic compound represented byStructural Formula (101).

FIGS. 9A and 9B show ultraviolet-visible absorption spectra and emissionspectra of the organic compound represented by Structural Formula (101).

FIGS. 10A and 10B are ¹H NMR charts of 8-halogenatedbenzo[b]naphtho[1,2-d]furan.

FIG. 11 illustrates a light-emitting element.

FIG. 12 shows voltage-luminance characteristics of a light-emittingelement 1.

FIG. 13 shows luminance-current efficiency characteristics of thelight-emitting element 1.

FIG. 14 shows voltage-current characteristics of the light-emittingelement 1.

FIG. 15 shows current density-luminance characteristics of thelight-emitting element 1.

FIG. 16 shows an emission spectrum of the light-emitting element 1.

FIG. 17 shows reliability of the light-emitting element 1.

FIG. 18 shows voltage-luminance characteristics of a light-emittingelement 2 and a comparative light-emitting element 3.

FIG. 19 shows luminance-current efficiency characteristics of thelight-emitting element 2 and the comparative light-emitting element 3.

FIG. 20 shows voltage-current characteristics of the light-emittingelement 2 and the comparative light-emitting element 3.

FIG. 21 shows current density-luminance characteristics of thelight-emitting element 2 and the comparative light-emitting element 3.

FIG. 22 shows emission spectra of the light-emitting element 2 and thecomparative light-emitting element 3.

FIG. 23 shows reliability of each of the light-emitting element 2 andthe comparative light-emitting element 3.

FIGS. 24A and 24B show results of LC-MS analysis of the organic compoundrepresented by Structural Formula (100).

FIGS. 25A and 25B show results of LC-MS analysis of the organic compoundrepresented by Structural Formula (101).

FIGS. 26A and 26B are ¹H NMR charts of an organic compound representedby Structural Formula (138).

FIGS. 27A and 27B show ultraviolet-visible absorption spectra andemission spectra of the organic compound represented by StructuralFormula (138).

FIG. 28 shows voltage-luminance characteristics of a light-emittingelement 4.

FIG. 29 shows luminance-current efficiency characteristics of thelight-emitting element 4.

FIG. 30 shows voltage-current characteristics of the light-emittingelement 4.

FIG. 31 shows current density-luminance characteristics of thelight-emitting element 4.

FIG. 32 shows an emission spectrum of the light-emitting element 4.

FIG. 33 shows reliability of the light-emitting element 4.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention are described withreference to the drawings. Note that the present invention is notlimited to the following description, and various changes andmodifications can be made without departing from the spirit and scope ofthe present invention. Therefore, the present invention should not beconstrued as being limited to the description in the followingembodiments.

Embodiment 1

In this embodiment, novel organic compounds of embodiments of thepresent invention are described.

The organic compound of one embodiment of the present invention is afluorescent organic compound that emits blue light and has a structurein which benzonaphthofuranylamine is bonded to each of the 1-positionand the 6-position of a pyrene skeleton. Note that one mode of theorganic compound described in this embodiment is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Ar¹ and Ar² separately represent a substitutedor unsubstituted aryl group having 6 to 13 carbon atoms forming a ring;R¹ to R⁸ separately represent hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms,or a substituted or unsubstituted aryl group having 6 to 10 carbonatoms; and X¹ and X² separately represent a substituted or unsubstitutedbenzo[b]naphtho[1,2-d]furanyl group.

The organic compound represented by General Formula (G1) is preferablyan organic compound represented by General Formula (G2).

In General Formula (G2), Ar¹ and Ar² separately represent a substitutedor unsubstituted aryl group having 6 to 13 carbon atoms forming a ring;and R¹ to R¹⁷ and R¹⁹ to R²⁷ separately represent hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms.

The organic compound represented by General Formula (G1) is preferablyan organic compound represented by General Formula (G3). Note that theorganic compound represented by General Formula (G3) is preferablebecause its emission wavelength can be shorter.

In General Formula (G3), Ar¹ and Ar² separately represent a substitutedor unsubstituted aryl group having 6 to 13 carbon atoms forming a ring;and R¹ to R⁸, R¹⁰ to R¹⁸, and R²⁰ to R²⁸ separately represent hydrogen,a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, or a substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms. In a substance represented by GeneralFormula (G3), each of R¹⁸ and R²⁸ is preferably a substituted orunsubstituted phenyl group, in which case the emission wavelength of thesubstance can be short. The substance in which R¹⁸ and R²⁸ aresubstituted or unsubstituted phenyl groups is preferably used for alight-emitting element, in which case the light-emitting element has anemission spectrum with a narrow half-width, high emission efficiency,and high reliability. In order to prevent distortion of a stereostructure, R¹⁸ and R²⁸ are further preferably unsubstituted phenylgroups. In the case where R¹⁸ and R²⁸ are each a phenyl group having asubstituent, the substituent is preferably an alkyl group having 1 to 6carbon atoms or a phenyl group.

The organic compound represented by General Formula (G2) is preferablyan organic compound represented by General Formula (G4).

In General Formula (G4), R¹ to R⁸ and R²⁹ to R³⁸ separately representhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6carbon atoms, a cyano group, halogen, a substituted or unsubstitutedhaloalkyl group having 1 to 6 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 10 carbon atoms.

The organic compound represented by General Formula (G3) is preferablyan organic compound represented by General Formula (G5). Note that theorganic compound represented by General Formula (G5) is preferablebecause its emission wavelength can be shorter.

In General Formula (G5), R¹ to R⁸ and R²⁹ to R³⁸ separately representhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6carbon atoms, a cyano group, halogen, a substituted or unsubstitutedhaloalkyl group having 1 to 6 carbon atoms, or a substituted orunsubstituted aryl group having 6 to 10 carbon atoms.

Specific examples of the substituted or unsubstituted aryl group having6 to 13 carbon atoms forming a ring in General Formulae (G1) to (G3) andthe substituted or unsubstituted aryl group having 6 to 10 carbon atomsin General Formulae (G4) and (G5) include a phenyl group, a 1-naphthylgroup, a 2-naphthyl group, an ortho-tolyl group, a meta-tolyl group, apara-tolyl group, an ortho-biphenyl group, a meta-biphenyl group, apara-biphenyl group, a 9,9-dimethyl-9H-fluoren-2-yl group, a9,9-diphenyl-9H-fluoren-2-yl group, a 9H-fluoren-2-yl group, apara-tert-butylphenyl group, and a mesityl group.

Specific examples of the substituted or unsubstituted alkyl groupshaving 1 to 6 carbon atoms in General Formulae (G1) to (G5) include amethyl group, an ethyl group, an n-propyl group, an isopropyl group, an-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group,an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a neopentyl group, an n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neo-hexyl group, a cyclohexylgroup, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutylgroup, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

Specific examples of the substituted or unsubstituted alkoxy groupshaving 1 to 6 carbon atoms, the cyano group, the halogen, and thesubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atomsin General Formulae (G1) to (G5) include a methoxy group, an ethoxygroup, an n-propoxy group, an isopropoxy group, an n-butoxy group, asec-butoxy group, an isobutoxy group, a tert-butoxy group, ann-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, atert-pentyloxy group, a neo-pentyloxy group, an n-hexyloxy group, anisohexyloxy group, a sec-hexyloxy group, a tert-hexyloxy group, aneo-hexyloxy group, a cyclohexyloxy group, a 3-methylpentyloxy group, a2-methylpentyloxy group, a 2-ethylbutoxy group, a 1,2-dimethylbutoxygroup, a 2,3-dimethylbutoxy group, a cyano group, fluorine, chlorine,bromine, iodine, and a trifluoromethyl group.

Note that the organic compound of one embodiment of the presentinvention has the structure in which benzonaphthofuranylamine is bondedto each of the 1-position and the 6-position of the pyrene skeleton.This structure enables effective conjugation length from the pyreneskeleton to benzonaphthofuranylamine to be increased. By increasing theeffective conjugation length, the emission peak wavelength can becontrolled to be optimal. Thus, an organic compound that emits bluelight with high color purity can be obtained in one embodiment of thepresent invention. Particularly in the case of benzonaphthofuranylaminein which an amine skeleton is bonded to the 8-position of abenzo[b]naphtho[1,2-d]furanyl group, the purity of blue can beincreased.

In the case of the structure in which benzonaphthofuranylamine is bondedto each of the 1-position and the 6-position of the pyrene skeleton asin the organic compound of one embodiment of the present invention,amine skeletons are stabilized by benzonaphtho furanyl groups and anincrease in the reliability is expected. Thus, in one embodiment of thepresent invention, an organic compound that has high efficiency and along lifetime can be obtained.

Next, specific structural formulae of the organic compounds ofembodiments of the present invention (General Formulae (G1) to (G5)) areshown (Structural Formulae (100) to (137)). Note that the presentinvention is not limited thereto.

Note that a variety of reactions can be applied to a method forsynthesizing the organic compounds of embodiments of the presentinvention. For example, synthesis reactions described below enable thesynthesis of the organic compound of one embodiment of the presentinvention represented by General Formula (G1).

An example of a method for synthesizing the organic compound of oneembodiment of the present invention represented by General Formula (G1)is described.

<<Method for Synthesizing Organic Compound Represented by GeneralFormula (G1)>>

The organic compound represented by General Formula (G1) can besynthesized by Synthesis Schemes (A-1) and (A-2) shown below. In otherwords, a pyrene compound (Compound 1), arylamine (Compound 2), andarylamine (Compound 3) are coupled as shown in Synthesis Scheme (A-1) toobtain a pyrene compound (Compound 4), and then the pyrene compound(Compound 4), halogenated aryl (Compound 5), and halogenated aryl(Compound 6) are coupled as shown in Synthesis Scheme (A-2), whereby theorganic compound (G1) of one embodiment of the present invention can beobtained.

In Synthesis Schemes (A-1) and (A-2), Ar¹ and Ar² separately represent asubstituted or unsubstituted aryl group having 6 to 13 carbon atomsforming a ring; X³ to X⁶ separately represent halogen, atrifluoromethanesulfonate group, a boronic acid group, an organoborongroup, a halogenated magnesium group, tin, an organotin group, or thelike; R¹ to R⁸ separately represent a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, a cyano group, halogen, a substitutedor unsubstituted haloalkyl group having 1 to 6 carbon atoms, or asubstituted or unsubstituted aryl group having 6 to 10 carbon atoms; andX¹ and X² separately represent a substituted or unsubstitutedbenzo[b]naphtho[1,2-d]furanyl group. Note that in Synthesis Schemes(A-1) and (A-2), Compound 2 and Compound 3 (i.e., Ar¹ and Ar²) arepreferably the same and Compound 5 and Compound 6 (i.e., X¹ and X², andX⁵ and X⁶) are preferably the same.

In the case where the Buchwald-Hartwig reaction using a palladiumcatalyst is employed in Synthesis Schemes (A-1) and (A-2), X³ to X⁶preferably represent halogen or a triflate group, and the halogen ispreferably iodine, bromine, or chlorine. In the reaction, a palladiumcompound such as bis(dibenzylideneacetone)palladium(0) or palladium(II)acetate and a ligand such as tri(tert-butyl)phosphine,tri(n-hexyl)phosphine, tricyclohexylphosphine,di(1-adamantyl)-n-butylphosphine, or2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl can be used. Inaddition, in the reaction, an organic base such as sodium tert-butoxide,an inorganic base such as potassium carbonate, cesium carbonate, orsodium carbonate, or the like can be used. Furthermore, in the reaction,toluene, xylene, benzene, tetrahydrofuran, dioxane, or the like can beused as a solvent. Note that reagents that can be used in the reactionare not limited thereto.

The reaction employed in Synthesis Schemes (A-1) and (A-2) is notlimited to the Buchwald-Hartwig reaction. The Migita-Kosugi-Stillecoupling reaction using an organotin compound, a coupling reaction usinga Grignard reagent, the Ullmann reaction using copper or a coppercompound, or the like can also be used.

The method for synthesizing the organic compound (G1) of one embodimentof the present invention is not limited to Synthesis Schemes (A-1) and(A-2). The organic compound (G1) of one embodiment of the presentinvention can also be obtained in such a manner that abenzo[b]naphtho[1,2-d]furan compound and the amine compound (Compound 2or Compound 3) are coupled to obtain an amine body of thebenzo[b]naphtho[1,2-d]furan compound, and then the amine body of thebenzo[b]naphtho[1,2-d]furan compound and the pyrene compound(Compound 1) are coupled.

Although the example of the method for synthesizing the organic compoundof one embodiment of the present invention is described above, thepresent invention is not limited to the example and another synthesismethod can be used.

The organic compound of one embodiment of the present invention emitsblue light with high color purity. Blue light emission havingchromaticity near the blue-color chromaticity defined by the nationaltelevision standards committee (NTSC), i.e., (x, y)=(0.14, 0.08), can beobtained. In addition, the organic compound of one embodiment of thepresent invention has a long lifetime. Furthermore, the organic compoundof one embodiment of the present invention emits fluorescence, and thuscan be used as a light-emitting material or a light-emitting substancefor a light-emitting element.

Thus, the use of the organic compound of one embodiment of the presentinvention can achieve a light-emitting element that emits blue lightwith high color purity and has a long lifetime, a light-emitting device,an electronic appliance, or a lighting device. In addition, the use ofthe organic compound of one embodiment of the present invention canprovide a light-emitting element, a light-emitting device, an electronicappliance, or a lighting device that has high emission efficiency.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Embodiment 2

In this embodiment, a light-emitting element in which the organiccompound described in Embodiment 1 as one embodiment of the presentinvention is used for a light-emitting layer is described with referenceto FIG. 1.

In a light-emitting element described in this embodiment, as illustratedin FIG. 1, an EL layer 102 including a light-emitting layer 113 isinterposed between a pair of electrodes (a first electrode (anode) 101and a second electrode (cathode) 103), and the EL layer 102 includes ahole-injection layer 111, a hole-transport layer 112, anelectron-transport layer 114, an electron-injection layer 115, acharge-generation layer (E) 116, and the like in addition to thelight-emitting layer 113.

When voltage is applied to such a light-emitting element, holes injectedfrom the first electrode 101 side and electrons injected from the secondelectrode 103 side recombine in the light-emitting layer 113 to raise alight-emitting substance to an excited state. The light-emittingsubstance in the excited state emits light when it returns to the groundstate.

The hole-injection layer 111 included in the EL layer 102 contains asubstance having a high hole-transport property and an acceptorsubstance. When electrons are extracted from the substance having a highhole-transport property owing to the acceptor substance, holes aregenerated. Thus, holes are injected from the hole-injection layer 111into the light-emitting layer 113 through the hole-transport layer 112.

The charge-generation layer (E) 116 contains a substance having a highhole-transport property and an acceptor substance. Electrons areextracted from the substance having a high hole-transport property owingto the acceptor substance, and the extracted electrons are injected fromthe electron-injection layer 115 having an electron-injection propertyinto the light-emitting layer 113 through the electron-transport layer114.

A specific example in which the light-emitting element described in thisembodiment is fabricated is described below.

As the first electrode (anode) 101 and the second electrode (cathode)103, a metal, an alloy, an electrically conductive compound, a mixturethereof, and the like can be used. Specific examples are indiumoxide-tin oxide (indium tin oxide (ITO)), indium oxide-tin oxidecontaining silicon or silicon oxide, indium oxide-zinc oxide (indiumzinc oxide), indium oxide containing tungsten oxide and zinc oxide, gold(Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr),molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd),and titanium (Ti). In addition, an element belonging to Group 1 or Group2 of the periodic table, for example, an alkali metal such as lithium(Li) or cesium (Cs), an alkaline earth metal such as calcium (Ca) orstrontium (Sr), magnesium (Mg), an alloy containing such an element(MgAg, AlLi), a rare earth metal such as europium (Eu) or ytterbium(Yb), an alloy containing such an element, graphene, and the like can beused. The first electrode (anode) 101 and the second electrode (cathode)103 can be formed by, for example, a sputtering method or an evaporationmethod (including a vacuum evaporation method).

A substance having a high hole-transport property is preferably used forthe hole-injection layer 111, the hole-transport layer 112, and thecharge-generation layer (E) 116. Specific examples of the substancehaving a hole-transport property include aromatic amine compounds suchas 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB ora-NPD),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′biphenyl]-4,4′-diamine(abbreviation: TPD), 4,4′,4″-tris(carbazol-9-yl)triphenylamine(abbreviation: TCTA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA),4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA), and4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB);3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1);3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2); and3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1). Other examples include carbazole derivativessuch as 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA).The substances listed here are mainly ones that have a hole mobility of10⁻⁶ cm²/Vs or higher. Note that any substance other than the substanceslisted here may be used as long as the hole-transport property is higherthan the electron-transport property.

As the substance having a high hole-transport property, a high molecularcompound such as poly(N-vinylcarbazole) (abbreviation: PVK),poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), orpoly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation:Poly-TPD) can also be used.

For the hole-injection layer 111 and the charge-generation layer (E)116, an acceptor substance is preferably used. Specific examples of theacceptor substance include transition metal oxides and oxides of metalsbelonging to Groups 4 to 8 of the periodic table. Specifically,molybdenum oxide is particularly preferable.

The light-emitting layer 113 is a layer containing a light-emittingsubstance. The light-emitting layer 313 may contain only alight-emitting substance; alternatively, an emission center substance(guest material) may be dispersed in a host material in thelight-emitting layer 313. Note that in the case where a host materialand a guest material are contained in the light-emitting layer 113, thehost material preferably has triplet excitation energy higher than thatof the guest material.

There is no particular limitation the material that can be used as thelight-emitting substance and the emission center substance in thelight-emitting layer 313, and light emitted from these substances may beeither fluorescence or phosphorescence. Thus, the organic compound ofone embodiment of the present invention can be used for thelight-emitting layer 313. Besides, for example, substances given belowthat emit fluorescence or phosphorescence can be given as thelight-emitting substance and the emission center substance.

Examples of the substance emitting fluorescence includeN,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S),4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA),4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine(abbreviation: 2YGAPPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene(abbreviation: TBP),4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPA),N,N″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA),N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: 2PCAPPA),N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPPA),N,N,N′,N′,N″,N″,N′″,N′″-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine(abbreviation: DBC1), coumarin 30,N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCABPhA),N-(9,10-diphenyl-2-anthryl)-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPABPhA),9,10-bis(1,1′-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine(abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine(abbreviation: DPhAPhA), coumarin 545T, N,N′-diphenylquinacridone(abbreviation: DPQd), rubrene,5,12-bis(1,1′-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT),2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile(abbreviation: DCM1),2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCM2),N,N′,N′,N′-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation:p-mPhTD),7,14-diphenyl-N,N′,N′N′-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine(abbreviation: p-mPhAFD),{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTI),{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[U]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTB),2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile(abbreviation: BisDCM), and2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: BisDCJTM).

Examples of the substance emitting phosphorescence includebis[2-(3′,5′-bistrifluoromethylphenyl)pyridinato-N,C^(2′)]iridium(III)picolinate (abbreviation: Ir(CF₃ppy)₂(pic)),bis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate (abbreviation: FIracac),tris(2-phenylpyridinato)iridium(III) (abbreviation: Ir(ppy)₃),bis(2-phenylpyridinato)iridium(III) acetylacetonate (abbreviation:Ir(ppy)₂(acac)), tris(acetylacetonato) (monophenanthroline)terbium(III)(abbreviation: Tb(acac)₃(Phen)), bis(benzo[h]quinolinato)iridium(III)acetylacetonate (abbreviation: Ir(bzq)₂(acac)),bis(2,4-diphenyl-1,3-oxazolato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: Ir(dpo)₂(acac)),bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C^(2′)}iridium(III)acetylacetonate (abbreviation: Ir(p-PF-ph)₂(acac)),bis(2-phenylbenzothiazolato-N,C²)iridium(III) acetylacetonate(abbreviation: Ir(bt)₂(acac)),bis[2-(2′-benzo[4,5-a]thienyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate (abbreviation: Ir(btp)₂(acac)),bis(1-phenylisoquinolinato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: Ir(piq)₂(acac)),(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviation: Ir(Fdpq)₂(acac)),(acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-Me)₂(acac)]),(acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-iPr)₂(acae)]),(acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III)(abbreviation: Ir(tppr)₂(acac)), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)₂(dpm)],(acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(tBuppm)₂(acac)]),(acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)(abbreviation: [Ir(dppm)₂(acac)]),2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II)(abbreviation: PtOEP), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: Eu(DBM)₃(Phen)), andtris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III)(abbreviation: Eu(TTA)₃(Phen)).

As the light-emitting substance, a thermally activated delayedfluorescence (TADF) material that converts triplet excitation energyinto luminescence and exhibits thermally activated delayed fluorescencecan also be used. Note that “delayed fluorescence” exhibited by the TADFmaterial refers to light emission having the same spectrum as normalfluorescence and an extremely long lifetime. The lifetime is 10⁻⁶seconds or longer, preferably 10⁻³ seconds or longer. Specific examplesof the TADF material include fullerene, a derivative thereof, anacridine derivative such as proflavine, and eosin. Other examplesinclude a metal-containing porphyrin, such as a porphyrin containingmagnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium(In), or palladium (Pd). Examples of the metal-containing porphyrininclude a protoporphyrin-tin fluoride complex (SnF₂(Proto IX)), amesoporphyrin-tin fluoride complex (SnF₂(Meso IX)), ahematoporphyrin-tin fluoride complex (SnF₂(Hemato IX)), a coproporphyrintetramethyl ester-tin fluoride complex (SnF₂(Copro III-4Me)), anoctaethylporphyrin-tin fluoride complex (SnF₂(OEP)), anetioporphyrin-tin fluoride complex (SnF₂(Etio I)), and anoctaethylporphyrin-platinum chloride complex (PtCl₂OEP). Alternatively,a heterocyclic compound including a π-electron rich heteroaromatic ringand a π-electron deficient heteroaromatic ring can be used, such as2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine(PIC-TRZ).

Preferable examples of the substance (i.e., host material) used fordispersing the organometallic iridium complex given above as thesubstance emitting phosphorescence include compounds having an arylamineskeleton, such as 2,3-bis(4-diphenylaminophenyl)quinoxaline(abbreviation: TPAQn) and NPB, carbazole derivatives such as CBP and4,4′,4″-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), andmetal complexes such as bis[2-(2-hydroxyphenyl)pyridinato]zinc(abbreviation: Znpp₂), bis[2-(2-hydroxyphenyl)benzoxazolato]zinc(abbreviation: Zn(BOX)₂),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (abbreviation:BAlq), and tris(8-quinolinolato)aluminum (abbreviation: Alq₃).Alternatively, a high molecular compound such as PVK can be used.

The electron-transport layer 114 is a layer containing a substancehaving a high electron-transport property. For the electron-transportlayer 114, a metal complex such as Alq₃,tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq₂), BAlq,Zn(BOX)₂, or bis[2-(2-hydroxyphenyl)benzothiazolato]zinc (abbreviation:Zn(BTZ)₂) can be used. A heteroaromatic compound such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7),3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: TAZ),3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen),bathocuproine (abbreviation: BCP), or4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) can alsobe used. A high molecular compound such as poly(2,5-pyridinediyl)(abbreviation: PPy),poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation:PF-Py) orpoly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation:PF-BPy) can also be used. The substances listed here are mainly onesthat have an electron mobility of 10⁻⁶ cm²/Vs or higher. Note that anysubstance other than the substances listed here may be used for theelectron-transport layer 114 as long as the electron-transport propertyis higher than the hole-transport property.

Furthermore, the electron-transport layer 114 is not limited to a singlelayer, and may be a stack of two or more layers each containing any ofthe substances given above.

The electron-injection layer 115 contains a substance having a highelectron-injection property. For the electron-injection layer 115, analkali metal, an alkaline earth metal, or a compound thereof, such aslithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF₂),or lithium oxide (LiO_(x)) can be used. A rare earth metal compound likeerbium fluoride (ErF₃) can also be used. The substances for forming theelectron-transport layer 114, which are given above, can also be used.

A composite material in which an organic compound and an electron donor(donor) are mixed may also be used for the electron-injection layer 115.Such a composite material is excellent in an electron-injection propertyand an electron-transport property because electrons are generated inthe organic compound by the electron donor. In this case, the organiccompound is preferably a material that is excellent in transporting thegenerated electrons. Specifically, for example, the substances forforming the electron-transport layer 114 (e.g., a metal complex or aheteroaromatic compound), which are given above, can be used. As theelectron donor, a substance showing an electron-donating property withrespect to the organic compound may be used. Specific examples are analkali metal, an alkaline earth metal, and a rare earth metal arepreferable, and lithium, cesium, magnesium, calcium, erbium, andytterbium. In addition, an alkali metal oxide or an alkaline earth metaloxide is preferable, and lithium oxide, calcium oxide, and barium oxideare given. A Lewis base such as magnesium oxide can also be used. Anorganic compound such as tetrathiafulvalene (abbreviation: TTF) can alsobe used.

Note that each of the above-described hole-injection layer 111,hole-transport layer 112, light-emitting layer 113, electron-transportlayer 114, electron-injection layer 115, and charge-generation layer (E)116 can be formed by a method such as an evaporation method (e.g., avacuum evaporation method), an ink-jet method, or a coating method.

In the above-described light-emitting element, current flows because ofa potential difference generated between the first electrode 101 and thesecond electrode 103 and holes and electrons are recombined in the ELlayer 102, whereby light is emitted. Then, the emitted light isextracted outside through one or both of the first electrode 101 and thesecond electrode 103. Thus, one or both of the first electrode 101 andthe second electrode 103 are electrodes having light-transmittingproperties.

The organic compound of one embodiment of the present invention is usedfor part of the above-described light-emitting element, so that thelight-emitting element can emit blue fluorescence with high color purityand have a long lifetime.

Note that the light-emitting element described in this embodiment is anexample of a light-emitting element fabricated using the organiccompound of one embodiment of the present invention. As a light-emittingdevice including the above-described light-emitting element, a passivematrix light-emitting device and an active matrix light-emitting devicecan be fabricated. It is also possible to fabricate a light-emittingdevice with a microcavity structure including a light-emitting elementdescribed in another embodiment, which is different from theabove-described light-emitting element. Each of the light-emittingdevices is included in the present invention.

Note that there is no particular limitation on the structure of thetransistor (FET) in the case of fabricating the active matrixlight-emitting device. For example, a staggered FET or an invertedstaggered FET can be used as appropriate. A driver circuit formed over aFET substrate may be formed of both an n-type FET and a p-type FET oronly either an n-type FET or a p-type FET. Furthermore, there is noparticular limitation on the crystallinity of a semiconductor film usedfor the FET. For example, either an amorphous semiconductor film or acrystalline semiconductor film can be used. Examples of a semiconductormaterial include Group IV semiconductors (e.g., silicon and gallium),compound semiconductors (including oxide semiconductors), and organicsemiconductors.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Embodiment 3

In this embodiment, as one embodiment of the present invention, alight-emitting element (hereinafter referred to as tandem light-emittingelement) in which a charge-generation layer is provided between aplurality of EL layers is described.

A light-emitting element described in this embodiment is a tandemlight-emitting element including a plurality of EL layers (a first ELlayer 202(1) and a second EL layer 202(2)) between a pair of electrodes(a first electrode 201 and a second electrode 204) as illustrated inFIG. 2A.

In this embodiment, the first electrode 201 functions as an anode, andthe second electrode 204 functions as a cathode. Note that the firstelectrode 201 and the second electrode 204 can have structures similarto those described in Embodiment 2. In addition, all or any of theplurality of EL layers (the first EL layer 202(1) and the second ELlayer 202(2)) may have structures similar to those described inEmbodiment 2. In other words, the structures of the first EL layer202(1) and the second EL layer 202(2) may be the same or different fromeach other and can be similar to those of the EL layers described inEmbodiment 2.

In addition, a charge-generation layer (I) 205 is provided between theplurality of EL layers (the first EL layer 202(1) and the second ELlayer 202(2)). The charge-generation layer (I) 205 has a function ofinjecting electrons into one of the EL layers and injecting holes intothe other of the EL layers when voltage is applied between the firstelectrode 201 and the second electrode 204. In this embodiment, whenvoltage is applied such that the potential of the first electrode 201 ishigher than that of the second electrode 204, the charge-generationlayer (I) 205 injects electrons into the first EL layer 202(1) andinjects holes into the second EL layer 202(2).

Note that in terms of light extraction efficiency, the charge-generationlayer (I) 205 preferably has a property of transmitting visible light(specifically, the charge-generation layer (I) 205 has a visible lighttransmittance of 40% or more). The charge-generation layer (I) 205functions even when it has lower conductivity than the first electrode201 or the second electrode 204.

The charge-generation layer (I) 205 may have either a structure in whichan electron acceptor (acceptor) is added to an organic compound having ahigh hole-transport property or a structure in which an electron donor(donor) is added to an organic compound having a high electron-transportproperty. Alternatively, both of these structures may be stacked.

In the case of the structure in which an electron acceptor is added toan organic compound having a high hole-transport property, as theorganic compound having a high hole-transport property, for example, anaromatic amine compound such as NPB, TPD, TDATA, MTDATA, or4,4′-bis[N-(Spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), or the like can be used. The substances listedhere are mainly ones that have a hole mobility of 10⁻⁶ cm²/Vs or higher.Note that any organic compound other than the compounds listed here maybe used as long as the hole-transport property is higher than theelectron-transport property.

As the electron acceptor,7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation:F₄-TCNQ), chloranil, and the like can be given. Transition metal oxidescan also be given. Oxide of metals belonging to Groups 4 to 8 of theperiodic table can also be given. Specifically, vanadium oxide, niobiumoxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide,manganese oxide, and rhenium oxide are preferable because of their highelectron-accepting properties. Among these, molybdenum oxide isespecially preferable because it is stable in the air, has a lowhygroscopic property, and is easy to handle.

On the other hand, in the case of the structure in which an electrondonor is added to an organic compound having a high electron-transportproperty, as the organic compound having a high electron-transportproperty, for example, a metal complex having a quinoline skeleton or abenzoquinoline skeleton, such as Alq, Almq₃, BeBq₂, or BAlq, or the likecan be used. Alternatively, a metal complex having an oxazole-basedligand or a thiazole-based ligand, such as Zn(BOX)₂ or Zn(BTZ)₂ can beused. Alternatively, in addition to such a metal complex, PBD, OXD-7,TAZ, Bphen, BCP, or the like can be used. The substances listed here aremainly ones that have an electron mobility of 10⁻⁶ cm²/Vs or higher.Note that any organic compound other than the compounds listed here maybe used as long as the electron-transport property is higher than thehole-transport property.

As the electron donor, it is possible to use an alkali metal, analkaline earth metal, a rare earth metal, metals belonging to Groups 2and 13 of the periodic table, or an oxide or carbonate thereof.Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca),ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or thelike is preferably used. Alternatively, an organic compound such astetrathianaphthacene may be used as the electron donor.

Note that forming the charge-generation layer (I) 205 by using any ofthe above materials can suppress a drive voltage increase caused by thestack of the EL layers.

Although the light-emitting element including two EL layers is describedin this embodiment, the present invention can be similarly applied to alight-emitting element in which n EL layers (202(1) to 202(n)) (n isthree or more) are stacked as illustrated in FIG. 2B. In the case wherea plurality of EL layers are included between a pair of electrodes as inthe light-emitting element according to this embodiment, by providingcharge-generation layers (I) (205(1) to 205(n−1)) between the EL layers,light emission in a high luminance region can be obtained with currentdensity kept low. Since the current density can be kept low, the elementcan have a long lifetime. When the light-emitting element is applied tolighting, voltage drop due to resistance of an electrode material can bereduced, which results in homogeneous light emission in a large area. Inaddition, a low-power-consumption light-emitting device that can bedriven at low voltage can be achieved.

When the EL layers have different emission colors, a desired emissioncolor can be obtained from the whole light-emitting element. Forexample, in the light-emitting element having two EL layers, when anemission color of the first EL layer and an emission color of the secondEL layer are made to be complementary colors, a light-emitting elementemitting white light as a whole light-emitting element can also beobtained. Note that “complementary colors” refer to colors that canproduce an achromatic color when mixed. In other words, emission ofwhite light can be obtained by mixture of light emitted from substanceswhose emission colors are complementary colors.

The same can be applied to a light-emitting element having three ELlayers. For example, the light-emitting element as a whole can providewhite light emission when the emission color of the first EL layer isred, the emission color of the second EL layer is green, and theemission color of the third EL layer is blue.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Embodiment 4

In this embodiment, a light-emitting device including a light-emittingelement in which the organic compound of one embodiment of the presentinvention is used for a light-emitting layer is described.

The light-emitting device may be either a passive matrix typelight-emitting device or an active matrix type light-emitting device.Note that any of the light-emitting elements described in the otherembodiments can be used for the light-emitting device described in thisembodiment.

In this embodiment, an active matrix light-emitting device is describedwith reference to FIGS. 3A and 3B.

Note that FIG. 3A is a top view illustrating a light-emitting device andFIG. 3B is a cross-sectional view taken along the chain line A-A′ inFIG. 3A. The active matrix light-emitting device according to thisembodiment includes a pixel portion 302 provided over an elementsubstrate 301, a driver circuit portion (a source line driver circuit)303, and driver circuit portions (gate line driver circuits) 304 a and304 b. The pixel portion 302, the driver circuit portion 303, and thedriver circuit portions 304 a and 304 b are sealed between the elementsubstrate 301 and a sealing substrate 306 with a sealant 305.

In addition, over the element substrate 301, a lead wiring 307 forconnecting an external input terminal, through which a signal (e.g., avideo signal, a clock signal, a start signal, a reset signal, or thelike) or electric potential from the outside is transmitted to thedriver circuit portion 303 and the driver circuit portions 304 a and 304b, is provided. Here, an example is described in which a flexibleprinted circuit (FPC) 308 is provided as the external input terminal.Although only the FPC is illustrated here, the FPC may be provided witha printed wiring board (PWB). The light-emitting device in thisspecification includes, in its category, not only the light-emittingdevice itself but also the light-emitting device provided with the FPCor the PWB.

Next, a cross-sectional structure is described with reference to FIG.3B. The driver circuit portion and the pixel portion are formed over theelement substrate 301; the driver circuit portion 303 that is the sourceline driver circuit and the pixel portion 302 are illustrated here.

The driver circuit portion 303 is an example where a CMOS circuit isformed, which is a combination of an n-channel FET 309 and a p-channelFET 310. Note that any of various circuits such as a CMOS circuit, aPMOS circuit, or an NMOS circuit can be used as a circuit included inthe driver circuit portion. Although this embodiment shows a driverintegrated type in which the driver circuit is formed over thesubstrate, the driver circuit is not necessarily formed over thesubstrate, and may be formed outside the substrate.

The pixel portion 302 includes a plurality of pixels each of whichincludes a switching FET 311, a current control FET 312, and a firstelectrode (anode) 313 that is electrically connected to a wiring (asource electrode or a drain electrode) of the current control FET 312.Note that an insulator 314 is formed to cover end portions of the firstelectrode (anode) 313. In this embodiment, the insulator 314 is formedusing a positive photosensitive acrylic resin.

The insulator 314 preferably has a curved surface with curvature at anupper end portion or a lower end portion thereof in order to obtainfavorable coverage by a film that is to be stacked over the insulator314. Note that the insulator 514 can be formed using, for example,either a negative photosensitive resin or a positive photosensitiveresin. The material of the insulator 314 is not limited to an organiccompound and an inorganic compound such as silicon oxide or siliconoxynitride can also be used.

An EL layer 315 and a second electrode (cathode) 316 are stacked overthe first electrode (anode) 313. In the EL layer 315, at least alight-emitting layer is provided, and the light-emitting layer containsthe organic compound of one embodiment of the present invention. In theEL layer 315, a hole-injection layer, a hole-transport layer, anelectron-transport layer, an electron-injection layer, acharge-generation layer, and the like can be provided as appropriate inaddition to the light-emitting layer.

The stacked structure of the first electrode (anode) 313, the EL layer315, and the second electrode (cathode) 316 forms a light-emittingelement 317. For the first electrode (anode) 313, the EL layer 315, andthe second electrode (cathode) 316, any of the materials listed inEmbodiment 2 can be used. Although not illustrated, the second electrode(cathode) 316 is electrically connected to the FPC 308 that is anexternal input terminal.

Although the cross-sectional view of FIG. 3B illustrates only onelight-emitting element 317, a plurality of light-emitting elements isarranged in matrix in the pixel portion 302. Light-emitting elementsthat emit light of three kinds of colors (R, G, and B) are selectivelyformed in the pixel portion 302, whereby a light-emitting device capableof full color display can be obtained. Alternatively, a light-emittingdevice that is capable of full color display may be fabricated by acombination with color filters.

Furthermore, the sealing substrate 306 is attached to the elementsubstrate 301 with the sealant 305, so that the light-emitting element317 is provided in a space 318 surrounded by the element substrate 301,the sealing substrate 306, and the sealant 305. The space 318 may befilled with an inert gas (e.g., nitrogen or argon) or the sealant 305.

An epoxy-based resin or glass frit is preferably used for the sealant305. The material preferably allows as little moisture and oxygen aspossible to penetrate. As the sealing substrate 306, a glass substrate,a quartz substrate, or a plastic substrate formed of fiber reinforcedplastic (FRP), poly(vinyl fluoride) (PVF), polyester, acrylic, or thelike can be used. In the case where glass frit is used as the sealant,the element substrate 301 and the sealing substrate 306 are preferablyglass substrates in terms of adhesion.

As described above, the active matrix light-emitting device can befabricated.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Embodiment 5

In this embodiment, examples of a variety of electronic appliances thatare completed using a light-emitting device will be described withreference to FIGS. 4A to 4D. The light-emitting device is fabricatedusing the light-emitting element of one embodiment of the presentinvention.

Examples of electronic appliances that include the light-emitting deviceinclude television devices (also referred to as TV or televisionreceivers), monitors for computers and the like, cameras such as digitalcameras and digital video cameras, digital photo frames, cellular phones(also referred to as portable telephone devices), portable gamemachines, portable information terminals, audio playback devices, andlarge game machines such as pin-ball machines. Specific examples of theelectronic appliances are shown in FIGS. 4A to 4D.

FIG. 4A illustrates an example of a television device. In the televisiondevice 7100, a display portion 7103 is incorporated in a housing 7101.Images can be displayed by the display portion 7103, and thelight-emitting device can be used for the display portion 7103. Inaddition, here, the housing 7101 is supported by a stand 7105.

The television device 7100 can be operated by an operation switch of thehousing 7101 or a separate remote controller 7110. With operation keys7109 of the remote controller 7110, channels and volume can becontrolled and images displayed on the display portion 7103 can becontrolled. Furthermore, the remote controller 7110 may be provided witha display portion 7107 for displaying data output from the remotecontroller 7110.

Note that the television device 7100 is provided with a receiver, amodem, and the like. With the use of the receiver, general televisionbroadcasts can be received. Moreover, when the television device isconnected to a communication network with or without wires via themodem, one-way (from a sender to a receiver) or two-way (between asender and a receiver or between receivers) information communicationcan be performed.

FIG. 4B illustrates a computer, which includes a main body 7201, ahousing 7202, a display portion 7203, a keyboard 7204, an externalconnection port 7205, a pointing device 7206, and the like. Note thatthis computer can be manufactured using the light-emitting device forthe display portion 7203.

FIG. 4C illustrates a smart watch, which includes a housing 7302, adisplay panel 7304, operation buttons 7311 and 7312, a connectionterminal 7313, a band 7321, a clasp 7322, and the like.

The display panel 7304 mounted in the housing 7302 serving as a bezelincludes a non-rectangular display region. The display panel 7304 candisplay an icon 7305 indicating time, another icon 7306, and the like.

The smart watch in FIG. 4C can have a variety of functions, for example,a function of displaying a variety of information (e.g., a still image,a moving image, and a text image) on a display portion, a touch panelfunction, a function of displaying a calendar, date, time, and the like,a function of controlling processing with a variety of software(programs), a wireless communication function, a function of beingconnected to a variety of computer networks with a wirelesscommunication function, a function of transmitting and receiving avariety of data with a wireless communication function, and a functionof reading program or data stored in a recording medium and displayingthe program or data on a display portion.

The housing 7302 can include a speaker, a sensor (a sensor having afunction of measuring force, displacement, position, speed,acceleration, angular velocity, rotational frequency, distance, light,liquid, magnetism, temperature, chemical substance, sound, time,hardness, electric field, current, voltage, electric power, radiation,flow rate, humidity, gradient, oscillation, odor, or infrared rays), amicrophone, and the like. Note that the smart watch can be manufacturedusing the light-emitting device for the display panel 7304.

FIG. 4D illustrates an example of a mobile phone. A mobile phone 7400includes a display portion 7402 incorporated in a housing 7401, anoperation button 7403, an external connection port 7404, a speaker 7405,a microphone 7406, and the like. Note that the mobile phone 7400 ismanufactured using the light-emitting device for the display portion7402.

When the display portion 7402 of the mobile phone 7400 illustrated inFIG. 4D is touched with a finger or the like, data can be input to themobile phone 7400. In addition, operations such as making a call andcomposing an e-mail can be performed by touch on the display portion7402 with a finger or the like.

There are mainly three screen modes of the display portion 7402. Thefirst mode is a display mode mainly for displaying an image. The secondmode is an input mode mainly for inputting data such as characters. Thethird mode is a display-and-input mode in which two modes of the displaymode and the input mode are combined.

For example, in the case of making a call or creating e-mail, acharacter input mode mainly for inputting characters is selected for thedisplay portion 7402 so that characters displayed on the screen can beinput. In this case, it is preferable to display a keyboard or numberbuttons on almost the entire screen of the display portion 7402.

When a detection device including a sensor for detecting inclination,such as a gyroscope or an acceleration sensor, is provided inside themobile phone 7400, display on the screen of the display portion 7402 canbe automatically changed by determining the orientation of the mobilephone 7400 (whether the mobile phone is placed horizontally orvertically for a landscape mode or a portrait mode).

The screen modes are changed by touch on the display portion 7402 oroperation with the operation button 7403 of the housing 7401. The screenmodes can be switched depending on the kind of images displayed on thedisplay portion 7402. For example, when a signal of an image displayedon the display portion is a signal of moving image data, the screen modeis switched to the display mode. When the signal is a signal of textdata, the screen mode is switched to the input mode.

Moreover, in the input mode, when input by touching the display portion7402 is not performed within a specified period while a signal detectedby an optical sensor in the display portion 7402 is detected, the screenmode may be controlled so as to be switched from the input mode to thedisplay mode.

The display portion 7402 may function as an image sensor. For example,an image of a palm print, a fingerprint, or the like is taken by touchon the display portion 7402 with the palm or the finger, wherebypersonal authentication can be performed. In addition, when a backlightor a sensing light source that emits near-infrared light is provided inthe display portion, an image of a finger vein, a palm vein, or the likecan be taken.

As described above, the electronic appliances can be obtained using thelight-emitting device of one embodiment of the present invention. Thelight-emitting device has a remarkably wide application range, and thuscan be used for electronic appliances in a variety of fields.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Embodiment 6

In this embodiment, examples of a lighting device in which alight-emitting device including the organic compound of one embodimentof the present invention is used are described with reference to FIG. 5.

FIG. 5 illustrates an example in which the light-emitting device is usedas an indoor lighting device 8001. Since the light-emitting device canhave a large area, it can be used for a lighting device having a largearea. In addition, a lighting device 8002 in which a light-emittingregion has a curved surface can also be obtained with the use of ahousing with a curved surface. A light-emitting element included in thelight-emitting device described in this embodiment is in a thin filmform, which allows the housing to be designed more freely. Therefore,the lighting device can be elaborately designed in a variety of ways. Inaddition, a wall of the room may be provided with a large-sized lightingdevice 8003.

When the light-emitting device is used for a table by being used as asurface of a table, a lighting device 8004 that has a function as atable can be obtained. When the light-emitting device is used as part ofother furniture, a lighting device that has a function as the furniturecan be obtained.

As described above, a variety of lighting devices in which thelight-emitting device is used can be obtained. Note that these lightingdevices are also embodiments of the present invention.

Note that the structure described in this embodiment can be combined asappropriate with any of the structures described in the otherembodiments.

Example 1 Synthesis Example 1

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine](abbreviation:1,6BnfAPrn), an organic compound of one embodiment of the presentinvention represented by Structural Formula (100) in Embodiment 1, isdescribed. Note that a structure of 1,6BnfAPrn is shown below.

Step 1: Synthesis of 6-iodobenzo[b]naphtho[1,2-d]furan

Into a 500 mL three-neck flask were put 12 g (55 mmol) ofbenzo[b]naphtho[1,2-d]furan and 220 mL of tetrahydrofuran, and the airin the flask was replaced with nitrogen. Then, this solution was cooledto −80° C. Then, 40 mL (64 mmol) of n-butyllithium (a 1.6 mol/L n-hexanesolution) was dropped into this solution with a syringe at −80° C. Afterthe drop, the resulting solution was stirred at room temperature for 1hour.

After the stirring, this solution was cooled to −80° C. Then, a solutionin which 17 g (66 mmol) of iodine had been dissolved in 60 mL oftetrahydrofuran was dropped into this solution with a dripping funnel at−80° C. After the drop, this solution was stirred for 17 hours while itstemperature was returned to room temperature. After the stirring, anaqueous solution of sodium thiosulfate was added to the resultingmixture, and the mixture was stirred for 1 hour. After the stirring, anorganic layer of this mixture was washed with water and a saturatedaqueous solution of sodium hydrogen carbonate, and then magnesiumsulfate was added to the organic layer. The mixture was gravity-filteredto give a filtrate, and then the filtrate was concentrated to give asolid.

The resulting solid was recrystallized from toluene/hexane to give apale brown solid. Ethanol was added to the resulting solid, irradiationwith ultrasonic waves was performed, and a solid was collected bysuction filtration to give 11 g (31 mmol) of pale yellow powder of thetarget substance in 56% yield. A synthesis scheme of Step 1 is shown in(a-1).

Step 2: Synthesis ofN,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine](abbreviation:1,6BnfAPrn)

Into a 300 mL three-neck flask were put 1.2 g (3.3 mmol) of1,6-dibromopyrene, 1.5 g (15 mmol) of sodium tert-butoxide, and 80 mg(0.14 mmol) of bis(dibenzylideneacetone)palladium(0), and the air in theflask was replaced with nitrogen. Then, 15 mL of toluene, 0.6 mL ofaniline, and 0.5 mL of tri(tert-butyl)phosphine (10% hexane solution)were added to the mixture.

The resulting mixture was stirred at 80° C. for 5 hours, and then 2.3 g(6.6 mmol) of 6-iodobenzo[b]naphtho[1,2-d]furan, 0.50 g (5.1 mmol) ofsodium tert-butoxide, 0.5 mL of tri(tert-butyl)phosphine (10% hexanesolution), and 80 mg (0.14 mmol) ofbis(dibenzylideneacetone)palladium(0) were added to the mixture. Theresulting mixture was stirred at 80° C. for 17 hours. After apredetermined period of time, the resulting mixture was filtered throughCelite (Catalog No. 531-16855 produced by Wako Pure Chemical Industries,Ltd.) to give a filtrate. The obtained filtrate was concentrated to givea solid. The solid was washed with ethanol and toluene to give 1.2 g(1.5 mmol) of a yellow solid of the target substance in 46% yield.

By a train sublimation method, 1.3 g of the obtained yellow solid waspurified by sublimation. The purification by sublimation was conductedby heating the yellow solid at 340° C. under a pressure of 1.0×10⁻² Paor lower. As a result of the purification by sublimation, 0.62 g of ayellow solid was recovered in 51% yield. A synthesis scheme of Step 2 isshown in (a-2).

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained in Step 2 are described below. FIGS. 6A and 6Bare ¹H NMR charts. The ¹H NMR charts revealed that 1,6BnfAPrn, theorganic compound of one embodiment of the present invention representedby Structural Formula (100), was obtained in Synthesis Example 1.

¹H NMR (CDCl₃, 500 MHz): δ=6.94 (d, J=7.5 Hz, 4H), 6.99 (t, J=7.5 Hz,2H), 7.20 (t, J=7.8 Hz, 4H), 7.41-7.50 (m, 10H), 7.61 (t, J=7.5 Hz, 2H),7.68 (d, J=8.0 Hz, 2H), 7.90 (d, J=9.5 Hz, 2H), 7.95 (d, J=8.5 Hz, 2H),8.09 (d, J=8.0 Hz, 2H), 8.30 (d, J=9.0 Hz, 2H), 8.43 (d, J=7.0 Hz, 2H),8.60 (d, J=8.0 Hz, 2H).

Next, an ultraviolet-visible absorption spectrum (hereinafter, simplyreferred to as “absorption spectrum”) and an emission spectrum of1,6BnfAPrn in a toluene solution were measured. The absorption spectrumwas measured at room temperature with an ultraviolet-visible lightspectrophotometer (V-550, manufactured by JASCO Corporation) in a statewhere the toluene solution was put in a quartz cell. The emissionspectrum was measured with a fluorescence spectrophotometer (FS920,manufactured by Hamamatsu Photonics Corporation) at room temperature ina state where the toluene solution was put in the quartz cell. FIG. 7Ashows measurement results of the absorption spectrum and the emissionspectrum. The horizontal axis represents wavelength (nm) and thevertical axis represents absorption intensity (arbitrary unit) andemission intensity (arbitrary unit). In FIG. 7A, two solid lines areshown: a thin line represents the absorption spectrum and a thick linerepresents the emission spectrum. The absorption spectrum shown in FIG.7A is a result obtained by subtraction of an absorption spectrum of onlytoluene in a quartz cell from the measured absorption spectrum of thetoluene solution in the quartz cell.

As shown in FIG. 7A, 1,6BnfAPrn that is the organic compound of oneembodiment of the present invention has an emission peak at 459 nm,which means that blue light emission was observed in the toluenesolution.

FIG. 7B shows an absorption spectrum and an emission spectrum of a thinfilm of 1,6BnfAPrn. The absorption spectrum was measured with anultraviolet-visible spectrophotometer (V-550, produced by JASCOCorporation). The measurement was performed with samples each preparedin such a manner that the thin film was deposited on a quartz substrate.The absorption spectrum was obtained by subtraction of an absorptionspectrum of only the quartz substrate from absorption spectra of thethin film on the quartz substrate. In FIG. 7B, the horizontal axisrepresents wavelength (nm) and the vertical axis represents absorptionintensity (arbitrary unit).

Next, 1,6BnfAPrn obtained in this example was analyzed by liquidchromatography mass spectrometry (LC-MS).

In the analysis by LC-MS, liquid chromatography (LC) separation wascarried out with UltiMate 3000 manufactured by Thermo Fisher ScientificK.K., and mass spectrometry (MS) analysis was carried out with QExactive manufactured by Thermo Fisher Scientific K.K, ACQUITY UPLC BEHC8 (2.1×100 mm, 1.7 μm) was used as a column for the LC separation, andthe column temperature was 40° C. Acetonitrile was used for Mobile PhaseA and a 0.1% formic acid aqueous solution was used for Mobile Phase B. Asample was prepared in such a manner that 1,6BnfAPrn was dissolved intoluene at a given concentration and the mixture was diluted withacetonitrile. The injection amount was 10.0 μL.

In the MS analysis, ionization was carried out by an electrosprayionization (ESI) method, and measurement was carried out bytargeted-MS². Conditions of an ion source were set as follows: the flowrates of a sheath gas, an Aux gas, and a Sweep gas were 50, 10, and 0,respectively, the spray voltage was 3.5 kV, the capillary temperaturewas 350° C., the S lens voltage was 55.0, and the HESI heatertemperature was 350° C. The resolution was 70000, the AGC target was3e6, the mass range was m/z=112 to 1690, and the detection was performedin a positive mode.

A component with m/z of 817.28250±10 ppm that underwent the ionizationunder the above-described conditions was collided with an argon gas in acollision cell to dissociate into product ions, and MSMS measurement wascarried out. FIGS. 24A and 24B show detection results of ions, whichwere generated under a normalized collision energy (NCE) for thecollision with argon of 50, with a Fourier transform mass spectrometer(FT MS).

The results in FIGS. 24A and 24B demonstrate that product ions of1,6BnfAPrn, the organic compound of one embodiment of the presentinvention represented by Structural Formula (100), are detected ataround m/z=218 and m/z=202. Note that the results in FIGS. 24A and 24Bshow characteristics derived from 1,6BnfAPrn and thus can be regarded asimportant data for identifying 1,6BnfAPrn contained in a mixture.

The product ion around m/z=218 is presumed to be a cation derived frombenzo[b]naphtho[1,2-d]furan in the compound represented by StructuralFormula (100), and this indicates a partial structure of 1,6BnfAPrn ofone embodiment of the present invention. In addition, the product ionaround m/z=202 is presumed to be a cation derived from pyrene, and thisindicates a partial structure of 1,6BnfAPrn, the organic compound of oneembodiment of the present invention.

Example 2 Synthesis Example 2

In this example, a method for synthesizingN,N-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation:1,6BnfAPrn-02), an organic compound of one embodiment of the presentinvention represented by Structural Formula (101) in Embodiment 1, isdescribed. Note that a structure of 1,6BnfAPrn-02 is shown below.

Step 1: Synthesis ofN,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation:1,6BnfAPrn-02)

Into a 50 mL three-neck flask were put 0.71 g (2.0 mmol) of1,6-dibromopyrene, 1.0 g (0.10 mmol) of sodium tert-butoxide, and 50 mg(0.087 mmol) of bis(dibenzylideneacetone)palladium(0), and the air inthe flask was replaced with nitrogen. Then, 10 mL of toluene, 0.4 mL ofaniline, and 0.3 mL of tri(tert-butyl)phosphine (10% hexane solution)were added to the mixture. The resulting mixture was stirred at 80° C.for 3 hours.

After a predetermined period of time, 1.0 g (4.0 mmol) of8-chlorobenzo[b]naphtho[1,2-d]furan, 0.18 g (0.44 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (abbreviation: S-Phos),and 50 mg (0.087 mmol) of bis(dibenzylideneacetone)palladium(0) wereadded to the mixture. The resulting mixture was stirred at 80° C. for 10hours. After a predetermined period of time, the resulting mixture wassuction-filtered through Celite (Catalog No. 531-16855 produced by WakoPure Chemical Industries, Ltd.) to give a filtrate. The obtainedfiltrate was concentrated to give a solid. The solid was recrystallizedfrom toluene/ethanol to give a brown solid.

The obtained solid was purified by silica gel column chromatography. Asa developing solvent, a mixed solvent of toluene and hexane in a ratioof 1:3 was used. An obtained fraction was concentrated to give a solid.The solid was recrystallized from toluene to give 1.3 g (1.6 mmol) of ayellow solid of the target substance in 82% yield.

By a train sublimation method, 1.3 g of the obtained yellow solid waspurified by sublimation. The purification by sublimation was conductedby heating the yellow solid at 350° C. at an argon flow rate of 10mL/min under a pressure of 2.6 Pa. As a result of the purification bysublimation, 0.78 g of a yellow solid was recovered in 58% yield. Asynthesis scheme of Step 2 is shown in (b-1).

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained in Step 1 are described below. FIGS. 8A and 8Bare ¹H NMR charts. The ¹H NMR charts revealed that 1,6BnfAPrn-02, whichis the organic compound of one embodiment of the present inventionrepresented by Structural Formula (101), was obtained in SynthesisExample 2.

¹H NMR (CDCl₃, 500 MHz): δ=6.90 (d, J=8.0 Hz, 4H), 6.95 (t, J=7.2 Hz,2H), 7.19 (t, J=8.0 Hz, 6H), 7.33 (t, J=8.0 Hz, 2H), 7.54 (d, J=8.0 Hz,2H), 7.57 (d, J=9.0 Hz, 2H), 7.73 (t, J=7.2 Hz, 2H), 7.86 (d, J=9.0 Hz,2H), 7.91 (d, J=9.0 Hz, 2H), 7.96 (d, J=8.5 Hz, 2H), 8.01 (d, J=9.0 Hz,2H), 8.10 (d, J=8.5 Hz, 2H), 8.17 (d, J=8.0 Hz, 2H), 8.29 (d, J=9.5 Hz,2H), 8.64 (d, J=8.5 Hz, 2H).

Next, an ultraviolet-visible absorption spectrum (hereinafter, simplyreferred to as “absorption spectrum”) and an emission spectrum of1,6BnfAPrn-02 in a toluene solution were measured. The absorptionspectrum was measured at room temperature with an ultraviolet-visiblelight spectrophotometer (V-550, manufactured by JASCO Corporation) in astate where the toluene solution was put in a quartz cell. The emissionspectrum was measured with a fluorescence spectrophotometer (FS920,manufactured by Hamamatsu Photonics Corporation) at room temperature ina state where the toluene solution was put in the quartz cell. FIG. 9Ashows measurement results of the absorption spectrum and the emissionspectrum. The horizontal axis represents wavelength (nm) and thevertical axis represents absorption intensity and emission intensity. InFIG. 9A, two solid lines are shown: a thin line represents theabsorption spectrum and a thick line represents the emission spectrum.The absorption spectrum shown in FIG. 9A is a result obtained bysubtraction of an absorption spectrum of only toluene in a quartz cellfrom the measured absorption spectrum of the toluene solution in thequartz cell.

As shown in FIG. 9A, 1,6BnfAPrn-02 that is the organic compound of oneembodiment of the present invention has an emission peak at 453 nm,which means that blue light emission was observed in the toluenesolution.

FIG. 9B shows an absorption spectrum and an emission spectrum of a thinfilm of 1,6BnfAPrn-02. The absorption spectrum was measured with anultraviolet-visible spectrophotometer (V-550, produced by JASCOCorporation). The measurement was performed with samples each preparedin such a manner that the thin film was deposited on a quartz substrate.The absorption spectrum was obtained by subtraction of an absorptionspectrum of only the quartz substrate from absorption spectra of thethin film on the quartz substrate. In FIG. 9B, the horizontal axisrepresents wavelength (nm) and the vertical axis represents absorptionintensity (arbitrary unit).

Next, 1,6BnfAPrn-02 obtained in this example was analyzed by liquidchromatography mass spectrometry (LC-MS).

In the analysis by LC-MS, liquid chromatography (LC) separation wascarried out with UltiMate 3000 manufactured by Thermo Fisher ScientificK.K., and mass spectrometry (MS) analysis was carried out with QExactive manufactured by Thermo Fisher Scientific K.K. ACQUITY UPLC BEHC8 (2.1×100 mm, 1.7 μm) was used as a column for the LC separation, andthe column temperature was 40° C. Acetonitrile was used for Mobile PhaseA and a 0.1% formic acid aqueous solution was used for Mobile Phase B. Asample was prepared in such a manner that 1,6BnfAPrn-02 was dissolved intoluene at a given concentration and the mixture was diluted withacetonitrile. The injection amount was 10.0 μL.

In the MS analysis, ionization was carried out by an electrosprayionization (ESI) method, and measurement was carried out bytargeted-MS². Conditions of an ion source were set as follows: the flowrates of a sheath gas, an Aux gas, and a Sweep gas were 50, 10, and 0,respectively, the spray voltage was 3.5 kV, the capillary temperaturewas 350° C., the S lens voltage was 55.0, and the HESI heatertemperature was 350° C. The resolution was 70000, the AGC target was3e6, the mass range was m/z=112 to 1690, and the detection was performedin a positive mode.

A component with m/z of 817.28250±10 ppm that underwent the ionizationunder the above-described conditions was collided with an argon gas in acollision cell to dissociate into product ions, and MSMS measurement wascarried out. FIGS. 25A and 25B show detection results of ions, whichwere generated under a normalized collision energy (NCE) for thecollision with argon of 50, with a Fourier transform mass spectrometer(FT MS).

The results in FIGS. 25A and 25B demonstrate that product ions of1,6BnfAPrn-02, the organic compound of one embodiment of the presentinvention represented by Structural Formula (101), are detected ataround m/z=218 and m/z=202. Note that the results in FIGS. 25A and 25Bshow characteristics derived from 1,6BnfAPrn-02 and thus can be regardedas important data for identifying 1,6BnfAPrn-02 contained in a mixture.

The product ion around m/z=218 is presumed to be a cation derived frombenzo[b]naphtho[1,2-d]furan in the compound represented by StructuralFormula (101), and this indicates a partial structure of 1,6BnfAPrn-02of one embodiment of the present invention. In addition, the product ionaround m/z=202 is presumed to be a cation derived from pyrene, and thisindicates a partial structure of 1,6BnfAPrn-02, the organic compound ofone embodiment of the present invention.

Example 3 Synthesis Example 3

In this example, a method for synthesizing8-chlorobenzo[b]naphtho[1,2-d]furan (abbreviation: 8-ClBnf), which isthe organic compound used in Example 2, is described. Note that astructure of 8-chlorobenzo[b]naphtho[1,2-d]furan is shown below.

Step 1: Synthesis of 3-chloro-2-fluorobenzeneboronic acid

Into a 500 mL three-neck flask was put 16 g (72 mmol) of1-bromo-3-chloro-2-fluorobenzene, and the air in the flask was replacedwith nitrogen. After that, 200 mL of tetrahydrofuran was added to thesolution, and this mixture solution was cooled down to −80° C. To thismixture solution, 48 mL (76 mmol) of n-BuLi (a 1.6 mol/L hexanesolution) was dropped with a syringe, and then the resulting mixture wasstirred at −80° C. for 1.5 hours.

After stirring, 9.0 mL (80 mmol) of trimethyl borate was added to thismixture. The mixture was stirred for approximately 19 hours while thetemperature of the mixture was being returned to room temperature. Afterthe stirring, approximately 100 mL of a 1 mol/L hydrochloric acid wasadded to the obtained solution, and the mixture was stirred. An organiclayer of this mixture was washed with water and an aqueous layer wassubjected to extraction with toluene twice. The extracted solution andthe organic layer were combined and washed with saturated saline. Theobtained organic layer was dried with magnesium sulfate, and thismixture was gravity-filtered. The obtained filtrate was concentrated togive 4.5 g of a pale yellow solid of the target substance in 35% yield.A synthesis scheme of Step 1 is shown in (c-1).

Step 2: Synthesis of 1-(3-chloro-2-fluorophenyl)-2-naphthol

Into a 200 mL three-neck flask were put 5.8 g (26 mmol) of1-bromo-2-naphthol, 4.5 g (26 mmol) of 3-chloro-2-fluorobenzeneboronicacid, and 0.40 g (1.3 mol) of tri(ortho-tolyl)phosphine, and the air inthe flask was replaced with nitrogen. To this mixture were added 150 mLof toluene, 50 mL of ethanol, and 21 mL of an aqueous solution ofpotassium carbonate (2.0 mol/L). The mixture was degassed by beingstirred while the pressure in the flask was reduced, and then the air inthe flask was replaced with nitrogen. To this mixture was added 58 mg(0.26 mmol) of palladium(II) acetate, and the resulting mixture wasstirred at 90° C. under a nitrogen stream for 7 hours.

After the stirring, an organic layer of the mixture was washed withwater, and then an aqueous layer was subjected to extraction withtoluene. The extracted solution combined with the organic layer waswashed with a saturated aqueous solution of sodium chloride, and theorganic layer was dried with magnesium sulfate. The resulting mixturewas gravity-filtered to give a filtrate. The obtained filtrate wasconcentrated to give a brown liquid. The liquid was purified by silicagel column chromatography using a mixed solvent (toluene: hexane=9:1) asa developing solvent to give 3.1 g of a brown liquid of the targetsubstance in 44% yield. A synthesis scheme of Step 2 is shown in (c-2).

Step 3: Synthesis of 8-Chlorobenzo[b]naphtho[1,2-d]furan

Into a 300 mL recovery flask were put 3.1 g (11 mmol) of1-(3-chloro-2-fluorophenyl)-2-naphthol, 70 mL of N-methyl-2-pyrrolidone,and 4.2 g (31 mmol) of potassium carbonate, and this mixture was stirredat 150° C. in the air for 7 hours. After the stirring, approximately 50mL of water and approximately 50 mL of hydrochloric acid (1.0 mol/L)were added to the resulting mixture.

To the resulting solution was added approximately 100 mL of ethylacetate, and then an aqueous layer was subjected to extraction withethyl acetate three times. The extracted solution and an organic layerwere combined and washed with a saturated aqueous solution of sodiumhydrogen carbonate and a saturated aqueous solution of sodium chloride,and magnesium sulfate was then added. This mixture was gravity-filteredto give a filtrate. The resulting filtrate was concentrated to give 2.9g of a pale brown solid of the target substance in 99% yield or higher.A synthetic scheme of Step 3 is shown in (c-3).

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe pale brown solid obtained in Step 3 are described below. FIGS. 10Aand 10B are ¹H NMR charts. The results revealed that8-chlorobenzo[b]naphtho[1,2-d]furan, which is the organic compoundsynthesized by the method described in Synthesis Example 3, wasobtained.

¹H NMR (CDCl₃, 500 MHz): δ=7.42 (t, J=4.7 Hz, 1H), 7.51 (d, 0.1=4.5 Hz,1H), 7.58 (t, J=4.5 Hz, 1H), 7.75 (t, J=4.5 Hz, 1H), 7.85 (d, J=5.4 Hz,1H), 7.98 (d, J=5.1 Hz, 1H), 8.05 (d, J=4.8 Hz, 1H), 8.30 (d, J=4.2 Hz,1H), 8.59 (d, J=4.8 Hz, 1H).

Example 4

In this example, a light-emitting element 1 was fabricated. In thelight-emitting element 1,1,6BnfAhm (Structural Formula (100)), theorganic compound of one embodiment of the present invention, was usedfor a light-emitting layer. An emission spectrum of the light-emittingelement 1 was measured. Note that the fabrication of the light-emittingelement 1 is described with reference to FIG. 11. Chemical formulae ofmaterials used in this example are shown below.

<<Fabrication of Light-Emitting Element 1>>

First, indium tin oxide containing silicon oxide (ITSO) was depositedover a glass substrate 900 by a sputtering method to form a firstelectrode 901 that functions as an anode. The thickness of the firstelectrode 901 was 110 nm. The electrode area was 2 mm×2 mm.

Next, as pretreatment for fabricating the light-emitting element 1 overthe substrate 900, UV ozone treatment was performed for 370 secondsafter washing of a surface of the substrate with water and baking thatwas performed at 200° C. for 1 hour.

After that, the substrate was transferred into a vacuum evaporationapparatus where the pressure had been reduced to approximately 10⁻⁴ Pa,and was subjected to vacuum baking at 170° C. for 30 minutes in aheating chamber of the vacuum evaporation apparatus, and then thesubstrate 900 was cooled down for approximately 30 minutes.

Next, the substrate 900 was fixed to a holder provided in the vacuumevaporation apparatus so that a surface of the substrate 900 over whichthe first electrode 901 was formed faced downward. In this example, acase is described in which a hole-injection layer 911, a hole-transportlayer 912, a light-emitting layer 913, an electron-transport layer 914,and an electron-injection layer 915, which are included in an EL layer902, are sequentially formed by a vacuum evaporation method.

After the pressure in the vacuum evaporation apparatus was reduced to10⁻⁴ Pa, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA) and molybdenum oxide were deposited byco-evaporation with a mass ratio of PCzPA to molybdenum oxide of 4:2 toform the hole-injection layer 911 on the first electrode 901. Thethickness of the hole-injection layer 911 was 50 nm. Note thatco-evaporation is an evaporation method in which a plurality ofdifferent substances are concurrently vaporized from differentevaporation sources.

Next, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA) was deposited to a thickness of 10 nm byevaporation to form the hole-transport layer 912.

Next, the light-emitting layer 913 was formed on the hole-transportlayer 912. CzPA and 1,6BnfAPrn were deposited by co-evaporation with amass ratio of CzPA to 1,6BnfAPrn of 1:0.01. The thickness of thelight-emitting layer 913 was 25 nm.

Next, on the light-emitting layer 913, CzPA was deposited by evaporationto a thickness of 10 nm and then bathophenanthroline (abbreviation:Bphen) was deposited by evaporation to a thickness of 15 nm to form theelectron-transport layer 914. Furthermore, lithium fluoride wasdeposited by evaporation to a thickness of 1 nm on theelectron-transport layer 914 to form the electron-injection layer 915.

Finally, aluminum was deposited by evaporation to a thickness of 200 nmon the electron-injection layer 915 to form a second electrode 903serving as a cathode. Thus, the light-emitting element 1 was obtained.Note that, in all the above evaporation steps, evaporation was performedby a resistance-heating method.

Table 1 shows an element structure of the light-emitting element 1obtained in the above-described manner.

TABLE 1 Hole- Hole- Light- Electron- First injection transport emittingElectron-transport injection Second electrode layer layer layer layerlayer electrode Light- ITSO PCzPA: PCzPA CzPA: CzPA Bphen LiF Alemitting (110 nm) MoOx (10 nm) 1,6BnfAPrn (10 nm) (15 nm) (1 nm) (200nm) element 1 (4:2 50 nm) (1:0.01 25 nm)

The fabricated light-emitting element 1 was sealed in a glove boxcontaining a nitrogen atmosphere so as not to be exposed to the air(specifically, a sealant was applied onto outer edges of the elements,and at the time of sealing, UV treatment was performed first and thenheat treatment was performed at 80° C. for 1 hour).

<<Operation Characteristics of Light-Emitting Element 1>>

Operation characteristics of the fabricated light-emitting element 1were measured. Note that the measurement was carried out at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 12 shows voltage-luminance characteristics of the light-emittingelement 1. In FIG. 12, the vertical axis represents luminance (cd/m²)and the horizontal axis represents voltage (V). FIG. 13 showsluminance-current efficiency characteristics of the light-emittingelement 1. In FIG. 13, the vertical axis represents current efficiency(cd/A) and the horizontal axis represents luminance (cd/m²). FIG. 14shows voltage-current characteristics of the light-emitting element 1.In FIG. 14, the vertical axis represents current (mA) and the horizontalaxis represents voltage (V). FIG. 15 shows current density-luminancecharacteristics of the light-emitting element 1. In FIG. 15, thevertical axis represents luminance (cd/m²) and the horizontal axisrepresents current density (mA/cm²).

According to FIG. 13, the light-emitting element 1 including 1,6BnfAPrn,the organic compound of one embodiment of the present invention, is ahighly efficient element. Table 2 shows initial values of maincharacteristics of the light-emitting element 1 at a luminance ofapproximately 730 cd/m².

TABLE 2 Current Current Power External Voltage Current densityChromaticity Luminance efficiency efficiency quantum (V) (mA) (mA/cm²)(x, y) (cd/m²) (cd/A) (lm/W) efficiency (%) Light- 3.1 0.54 14.0 (0.14,0.13) 730 5 5 5.2 emitting element 1

The above results revealed that the light-emitting element 1 fabricatedin this example emitted blue light with high color purity. In addition,the light-emitting element 1 had high current efficiency.

FIG. 16 shows an emission spectrum of the light-emitting element 1 thatwas obtained when current was applied to the light-emitting element 1 ata current density of 25 mA/cm². As shown in FIG. 16, the emissionspectrum of the light-emitting element 1 had a peak at around 457 nm,which indicates that the peak was derived from emission of 1,6BnfAPrnthat is the organic compound of one embodiment of the present invention.

The light-emitting element 1 was subjected to a reliability test.Results of the reliability test are shown in FIG. 17. In FIG. 17, thevertical axis represents normalized luminance (%) with an initialluminance of 100% and the horizontal axis represents driving time (h) ofthe element. Note that in the reliability test, the light-emittingelement 1 was driven under the conditions where the initial luminancewas set to 5000 cd/m² and the current density was constant. The resultsrevealed that the luminance of the light-emitting element 1 after39-hour driving was approximately 81% of the initial luminance. Thismeans that the light-emitting element 1 had a long lifetime.

Thus, the use of the organic compound of one embodiment of the presentinvention enables a light-emitting element with a long lifetime to beobtained.

Example 5

In this example, a light-emitting element 2 was fabricated. In thelight-emitting element 2, 1,6BnfAPrn-02 (Structural Formula (101)), theorganic compound of one embodiment of the present invention, was usedfor a light-emitting layer. In addition, a comparative light-emittingelement 3 containingN,N′-(pyrene-1,6-diyl)bis[(N-phenyldibenzofuran)-4-amine](abbreviation:1,6FrAPrn-II) instead of 1,6BnfAPrn-02 of the light-emitting element 2was fabricated in a similar method. The light-emitting element 2 and thecomparative light-emitting element 3 were compared. Note that thefabrication of the light-emitting element 2 and the comparativelight-emitting element 3 is described with reference to FIG. 11.Chemical formulae of materials used in this example are shown below.

<<Fabrication of Light-Emitting Element 2 and Comparative Light-EmittingElement 3>>

First, indium tin oxide containing silicon oxide (ITSO) was depositedover a glass substrate 900 by a sputtering method to form a firstelectrode 901 that functions as an anode. The thickness of the firstelectrode 901 was 110 nm. The electrode area was 2 mm×2 mm.

Next, as pretreatment for fabricating the light-emitting element 2 andthe comparative light-emitting element 3 over the substrate 900, UVozone treatment was performed for 370 seconds after washing of a surfaceof the substrate with water and baking that was performed at 200° C. for1 hour.

After that, the substrate was transferred into a vacuum evaporationapparatus where the pressure had been reduced to approximately 10⁻⁴ Pa,and was subjected to vacuum baking at 170° C. for 30 minutes in aheating chamber of the vacuum evaporation apparatus, and then thesubstrate 900 was cooled down for approximately 30 minutes.

Next, the substrate 900 was fixed to a holder provided in the vacuumevaporation apparatus so that a surface of the substrate 900 over whichthe first electrode 901 was formed faced downward. In this example, acase is described in which a hole-injection layer 911, a hole-transportlayer 912, a light-emitting layer 913, an electron-transport layer 914,and an electron-injection layer 915, which are included in an EL layer902, are sequentially formed by a vacuum evaporation method.

After the pressure in the vacuum evaporation apparatus was reduced to10⁻⁴ Pa, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA) and molybdenum oxide were deposited byco-evaporation with a mass ratio of PCzPA to molybdenum oxide of 4:2 toform the hole-injection layer 911 on the first electrode 901. Thethickness of the hole-injection layer 911 was 50 nm. Note thatco-evaporation is an evaporation method in which a plurality ofdifferent substances are concurrently vaporized from differentevaporation sources.

Next, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA) was deposited to a thickness of 10 nm byevaporation to form the hole-transport layer 912.

Next, the light-emitting layer 913 was foil Led on the hole-transportlayer 912. In the case of the light-emitting element 2, CzPA and1,6BnfAPrn-02 were deposited by co-evaporation with a mass ratio of CzPAto 1,6BnfAPrn-02 of 1:0.01. The thickness of the light-emitting layer913 of the light-emitting element 2 was 25 nm. In the case of thecomparative light-emitting element 3, CzPA and 1,6FrAPrn-II weredeposited by co-evaporation with a mass ratio of CzPA to 1,6FrAPrn-II of1:0.03. The thickness of the light-emitting layer 913 of the comparativelight-emitting element 3 was 25 nm.

Next, on the light-emitting layer 913, CzPA was deposited by evaporationto a thickness of 10 nm and then bathophenanthroline (abbreviation:Bphen) was deposited by evaporation to a thickness of 15 nm to form theelectron-transport layer 914. Furthermore, lithium fluoride wasdeposited by evaporation to a thickness of 1 nm on theelectron-transport layer 914 to form the electron-injection layer 915.

Finally, aluminum was deposited by evaporation to a thickness of 200 nmon the electron-injection layer 915 to form a second electrode 903serving as a cathode. Thus, the light-emitting element 2 and thecomparative light-emitting element 3 were obtained. Note that, in allthe above evaporation steps, evaporation was performed by aresistance-heating method.

Table 3 shows an element structure of the light-emitting element 2 andthe comparative light-emitting element 3 obtained in the above-describedmanner.

TABLE 3 Hole- Hole- Light- Electron- First injection transport emittingElectron-transport injection Second electrode layer layer layer layerlayer electrode Light-emitting ITSO PCzPA: PCzPA CzPA: CzPA Bphen LiF Alelement 2 (110 nm) MoOx (10 nm) 1,6BnfAPrn-02 (10 nm) (15 nm) (1 nm)(200 nm) (4:2 50 nm) (1:0.01 25 nm) Comparative ITSO PCzPA: PCzPA CzPA:CzPA Bphen LiF Al light-emitting (110 nm) MoOx (10 nm) 1,6FrAPrn-II (10nm) (15 nm) (1 nm) (200 nm) element 3 (4:2 50 nm) (1:0.03 25 nm)

The fabricated light-emitting element 2 and the comparativelight-emitting element 3 were each sealed in a glove box containing anitrogen atmosphere so as not to be exposed to the air (specifically, asealant was applied onto outer edges of the elements, and at the time ofsealing, UV treatment was performed first and then heat treatment wasperformed at 80° C. for 1 hour).

<<Operation Characteristics of Light-Emitting Element 2 and ComparativeLight-Emitting Element 3>>

Operation characteristics of the fabricated light-emitting element 2 andthe comparative light-emitting element 3 were measured. Note that themeasurement was carried out at room temperature (in an atmosphere keptat 25° C.).

FIG. 18 shows voltage-luminance characteristics of the light-emittingelement 2 and the comparative light-emitting element 3. In FIG. 18, thevertical axis represents luminance (cd/m²) and the horizontal axisrepresents voltage (V). FIG. 19 shows luminance-current efficiencycharacteristics of the light-emitting element 2 and the comparativelight-emitting element 3. In FIG. 19, the vertical axis representscurrent efficiency (cd/A) and the horizontal axis represents luminance(cd/m²). FIG. 20 shows voltage-current characteristics of thelight-emitting element 2 and the comparative light-emitting element 3.In FIG. 20, the vertical axis represents current (mA) and the horizontalaxis represents voltage (V). FIG. 21 shows current density-luminancecharacteristics of the light-emitting element 2 and the comparativelight-emitting element 3. In FIG. 21, the vertical axis representsluminance (cd/m²) and the horizontal axis represents current density(mA/cm²).

FIG. 19 revealed that the light-emitting element 2 including1,6BnfAPrn-02 that is the organic compound of one embodiment of thepresent invention has efficiency higher than the comparativelight-emitting element 3 at around 1000 cd/m². Table 4 shows initialvalues of main characteristics of the light-emitting element 2 and thecomparative light-emitting element 3.

TABLE 4 Current Current Power External Voltage Current densityChromaticity Luminance efficiency efficiency quantum (V) (mA) (mA/cm²)(x, y) (cd/m²) (cd/A) (lm/W) efficiency (%) Light-emitting 3.1 0.84 21(0.14, 0.10) 920 4.4 4.5 5.2 element 2 Comparative 3.1 1.16 28.9 (0.14,0.10) 1080 3.8 3.8 4.4 light-emitting element 3

The above results revealed that the light-emitting element 2 fabricatedin this example had higher current efficiency than the comparativelight-emitting element 3 though the light-emitting element 2 emits bluelight with color purity as high as that of the comparativelight-emitting element 3.

FIG. 22 shows emission spectra of the light-emitting element 2 and thecomparative light-emitting element 3 that were obtained when current wasapplied to the light-emitting elements at a current density of 25mA/cm². As shown in FIG. 22, the emission spectra of the light-emittingelement 2 and the comparative light-emitting element 3 both had peaks ataround 452 nm, which indicates that the peaks were derived from emissionof 1,6BnfAPrn-02, the organic compound of one embodiment of the presentinvention, and from emission of 1,6FrAPrn-II, the organic compound usedfor comparison.

The light-emitting element 2 and the comparative light-emitting element3 were subjected to reliability tests. Results of the reliability testsare shown in FIG. 23. In FIG. 23, the vertical axis representsnormalized luminance (%) with an initial luminance of 100% and thehorizontal axis represents driving time (h) of the elements. Note thatin the reliability tests, the light-emitting element 2 and thecomparative light-emitting element 3 were driven under the conditionswhere the initial luminance was set to 5000 cd/m² and the currentdensity was constant. The results demonstrated that the luminance of thelight-emitting element 2 after 100-hour driving was approximately 65% ofthe initial luminance. In other words, the light-emitting element 2 hada longer lifetime than the comparative light-emitting element 3 whoseluminance after 100-hour driving was 56% of the initial luminance. Thus,the light-emitting element 2 including the organic compound of oneembodiment of the present invention had not only high color purity butalso a longer lifetime than the comparative light-emitting element 3.The above results indicate that the use of 1,6BnfAPrn-02, the organiccompound that is one embodiment of the present invention and has astructure in which benzo[b]naphtho[1,2-d]furan is bonded to1,6-diaminopyrene, makes it possible to provide a light-emitting elementthat emits blue light with high color purity and has a longer lifetimethan the case of using 1,6FrAPrn-II, the organic compound that is usedfor comparison and has a structure in which dibenzofuran is bonded to1,6-diaminopyrene.

Thus, the use of the organic compound of one embodiment of the presentinvention enables a light-emitting element that has high efficiency anda long lifetime to be obtained.

Example 6 Synthesis Example 4

In this example, a method for synthesizingN,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation:1,6BnfAPrn-03), an organic compound of one embodiment of the presentinvention represented by Structural Formula (138) in Embodiment 1, isdescribed. Note that a structure of 1,6BnfAPrn-03 is shown below.

Step 1: Synthesis of 6-iodobenzo[b]naphtho[1,2-d]furan

Into a 500 mL three-neck flask were put 8.5 g (39 mmol) ofbenzo[b]naphtho[1,2-d]furan, and the air in the flask was replaced withnitrogen. Then, 195 mL of tetrahydrofuran was added thereto. Thissolution was cooled to −75° C. Then, 25 mL (40 mmol) of n-butyllithium(a 1.59 mol/L n-hexane solution) was dropped into this solution. Afterthe drop, the resulting solution was stirred at room temperature for 1hour.

After a predetermined period of time, the resulting solution was cooledto −75° C. Then, a solution in which 10 g (40 mmol) of iodine had beendissolved in 40 mL of THF was dropped into this solution. After thedrop, the resulting solution was stirred for 17 hours while thetemperature of the solution was returned to room temperature. After apredetermined period of time, an aqueous solution of sodium thiosulfatewas added to the mixture, and the resulting mixture was stirred for 1hour. Then, an organic layer of the mixture was washed with water anddried with magnesium sulfate. After the drying, the mixture wasgravity-filtered to give a solution. The resulting solution wassuction-filtered through Celite (Catalog No. 531-16855 produced by WakoPure Chemical Industries, Ltd.) and Florisil (Catalog No. 540-00135produced by Wako Pure Chemical Industries, Ltd.) to give a filtrate. Theresulting filtrate was concentrated to give a solid. The resulting solidwas recrystallized from toluene to give 6.0 g (18 mmol) of white powderof the target substance in 45% yield. A synthesis scheme of Step 1 isshown in (d-1).

Step 2: Synthesis of 6-phenylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 6.0 g (18 mmol) of6-iodobenzo[b]naphtho[1,2-d]furan, 2.4 g (19 mmol) of phenylboronicacid, 70 mL of toluene, 20 mL of ethanol, and 22 mL of an aqueoussolution of potassium carbonate (2.0 mol/L). This mixture was degassedby being stirred while the pressure was reduced. After the degassing,the air in the flask was replaced with nitrogen, and then 480 mg (0.42mmol) of tetrakis(triphenylphosphine)palladium(0) was added to themixture. The resulting mixture was stirred at 90° C. under a nitrogenstream for 12 hours.

After a predetermined period of time, water was added to the mixture,and an aqueous layer was extracted with toluene. The extracted solutionand an organic layer were combined, and the mixture was washed withwater and then dried with magnesium sulfate. The mixture wasgravity-filtered to give a filtrate. The resulting filtrate wasconcentrated to give a solid, and the resulting solid was dissolved intoluene. The resulting solution was suction-filtered through Celite(Catalog No. 531-16855 produced by Wako Pure Chemical Industries, Ltd.),Florisil (Catalog No. 540-00135 produced by Wako Pure ChemicalIndustries, Ltd.), and alumina to give a filtrate. The resultingfiltrate was concentrated to give a solid. The resulting solid wasrecrystallized from toluene to give a 4.9 g (17 mmol) of a white solidof the target substance in 93% yield. A synthesis scheme of Step 2 isshown in (d-2).

Step 3: Synthesis of 8-iodo-6-phenylbenzo[b]naphtho[1,2,d]furan

Into a 300 mL three-neck flask was put 4.9 g (17 mmol) of6-phenylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 87 mL of tetrahydrofuran (THF) was addedthereto. The resulting solution was cooled to −75° C. Then, 11 mL (18mmol) of n-butyllithium (a 1.59 mol/L n-hexane solution) was droppedinto the solution. After the drop, the resulting solution was stirred atroom temperature for 1 hour. After a predetermined period of time, theresulting solution was cooled to −75° C. Then, a solution in which 4.6 g(18 mmol) of iodine had been dissolved in 18 mL of THF was dropped intothe resulting solution.

The resulting solution was stirred for 17 hours while the temperature ofthe solution was returned to room temperature. After a predeterminedperiod of time, an aqueous solution of sodium thiosulfate was added tothe mixture, and the resulting mixture was stirred for 1 hour. Then, anorganic layer of the mixture was washed with water and dried withmagnesium sulfate. The mixture was gravity-filtered to give a filtrate.The resulting filtrate was suction-filtered through Celite (Catalog No.531-16855 produced by Wako Pure Chemical Industries, Ltd.), Florisil(Catalog No. 540-00135 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The resulting filtrate was concentratedto give a solid. The resulting solid was recrystallized from toluene togive 3.7 g (8.8 mmol) of a target white solid in 53% yield. A synthesisscheme of Step 3 is shown in (d-3).

Step 4: Synthesis of 1,6BnfAPrn-03

Into a 100 mL three-neck flask were put 0.71 g (2.0 mmol) of1,6-dibromopyrene, 1.0 g (10.4 mmol) of sodium-tert-butoxide, 10 mL oftoluene, 0.36 mL (4.0 mmol) of aniline, and 0.3 mL oftri(tert-butyl)phosphine (a 10 wt % hexane solution), and the air in theflask was replaced with nitrogen. To this mixture was added 50 mg (85μmol) of bis(dibenzylideneacetone)palladium(0), and the resultingmixture was stirred at 80° C. for 2 hours.

After a predetermined period of time, to the resulting mixture wereadded 1.7 g (4.0 mmol) of 8-iodo-6-phenylbenzo[b]naphtho[1,2,d]furan,180 mg (0.44 mmol) of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos), and 50 mg (85 mol) ofbis(dibenzylideneacetone)palladium(0), and the resulting mixture wasstirred at 100° C. for 15 hours. After a predetermined period of time,the resulting mixture was filtered through Celite (Catalog No. 531-16855produced by Wako Pure Chemical Industries, Ltd.) to give a filtrate. Theresulting filtrate was concentrated to give a solid. The resulting solidwas washed with ethanol and recrystallized from toluene to give 1.38 g(1.4 mmol) of a yellow solid of the target substance in 71% yield.

By a train sublimation method, 1.37 mg (1.4 mmol) of the resultingyellow solid was purified by sublimation. The purification bysublimation was conducted by heating the yellow solid at 370° C. at anargon flow rate of 10 mL/min under a pressure of under a pressure of 2.3Pa. As a result of the purification by sublimation, 0.68 g (0.70 mmol)of the yellow solid was recovered in 50% yield. A synthesis scheme ofStep 4 is shown in (d-4).

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained in Step 4 are described below. FIGS. 26A and26B are ¹H NMR charts. FIG. 26B is a chart where the range from 6.7(ppm) to 8.8 (ppm) on the horizontal axis (δ) in FIG. 26A is enlarged.The results revealed that 1,6BnfAPrn-03, the organic compoundsynthesized by the method described in Synthesis Example 4, wasobtained.

¹H NMR (dichloromethane-d2, 500 MHz): δ=6.88 (t, J=7.7 Hz, 4H),7.03-7.06 (m, 6H), 7.11 (t, J=7.5 Hz, 2H), 7.13 (d, J=8.0 Hz, 2H),7.28-7.32 (m, 8H), 7.37 (t, J=8.0 Hz, 2H), 7.59 (t, J=7.2 Hz, 2H), 7.75(t, J=7.7 Hz, 2H), 7.84 (d, J=9.0 Hz, 2H), 7.88 (d, J=8.0 Hz, 2H), 8.01(s, 2H), 8.07 (d, J=8.0 Hz, 4H), 8.14 (d, J=9.0 Hz, 2H), 8.21 (d, J=8.0Hz, 2H), 8.69 (d, J=8.5 Hz, 2H).

Next, an ultraviolet-visible absorption spectrum (hereinafter, simplyreferred to as “absorption spectrum”) and an emission spectrum of1,6BnfAPrn-03 in a toluene solution were measured. The absorptionspectrum was measured at room temperature with an ultraviolet-visiblelight spectrophotometer (V-550, manufactured by JASCO Corporation) in astate where the toluene solution was put in a quartz cell. The emissionspectrum was measured with a fluorescence spectrophotometer (FS920,manufactured by Hamamatsu Photonics Corporation) at room temperature ina state where the toluene solution was put in the quartz cell. FIG. 27Ashows measurement results of the absorption spectrum and the emissionspectrum. The horizontal axis represents wavelength (nm) and thevertical axis represents absorption intensity (arbitrary unit) andemission intensity (arbitrary unit). In FIG. 27A, two solid lines areshown: a thin line represents the absorption spectrum and a thick linerepresents the emission spectrum. The absorption spectrum shown in FIG.27A is a result obtained by subtraction of an absorption spectrum ofonly toluene in a quartz cell from the measured absorption spectrum ofthe toluene solution in the quartz cell.

As shown in FIG. 27A, 1,6BnfAPrn-03 that is the organic compound of oneembodiment of the present invention has an emission peak at 464 nm,which means that blue light emission was observed in the toluenesolution.

FIG. 27B shows an absorption spectrum and an emission spectrum of a thinfilm of 1,6BnfAPrn-03. The absorption spectrum was measured with anultraviolet-visible spectrophotometer (V-550, produced by JASCOCorporation). The measurement was performed with samples each preparedin such a manner that the thin film was deposited on a quartz substrate.The absorption spectrum was obtained by subtraction of an absorptionspectrum of only the quartz substrate from absorption spectra of thethin film on the quartz substrate. In FIG. 27B, the horizontal axisrepresents wavelength (nm) and the vertical axis represents absorptionintensity (arbitrary unit).

Example 7

In this example, a light-emitting element 4 was fabricated. In thelight-emitting element 4, 1,6BnfAPrn-03 (Structural Formula (138)), theorganic compound of one embodiment of the present invention, was usedfor a light-emitting layer. An emission spectrum of the light-emittingelement 1 was measured. Note that the fabrication of the light-emittingelement 4 is described with reference to FIG. 11. Chemical formulae ofmaterials used in this example are shown below.

<<Fabrication of Light-Emitting Element 4>>

First, indium tin oxide containing silicon oxide (ITSO) was depositedover a glass substrate 900 by a sputtering method to form a firstelectrode 901 that functions as an anode. The thickness of the firstelectrode 901 was 110 nm. The electrode area was 2 mm×2 mm.

Next, as pretreatment for fabricating the light-emitting element 4 overthe substrate 900, UV ozone treatment was performed for 370 secondsafter washing of a surface of the substrate with water and baking thatwas performed at 200° C. for 1 hour.

After that, the substrate was transferred into a vacuum evaporationapparatus where the pressure had been reduced to approximately 10⁻⁴ Pa,and was subjected to vacuum baking at 170° C. for 30 minutes in aheating chamber of the vacuum evaporation apparatus, and then thesubstrate 900 was cooled down for approximately 30 minutes.

Next, the substrate 900 was fixed to a holder provided in the vacuumevaporation apparatus so that a surface of the substrate 900 over whichthe first electrode 901 was formed faced downward. In this example, acase is described in which a hole-injection layer 911, a hole-transportlayer 912, a light-emitting layer 913, an electron-transport layer 914,and an electron-injection layer 915, which are included in an EL layer902, are sequentially formed by a vacuum evaporation method.

After the pressure in the vacuum evaporation apparatus was reduced to10⁻⁴ Pa, 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA) and molybdenum oxide were deposited byco-evaporation with a mass ratio of PCzPA to molybdenum oxide of 4:2 toform the hole-injection layer 911 on the first electrode 901. Thethickness of the hole-injection layer 911 was 50 nm. Note thatco-evaporation is an evaporation method in which a plurality ofdifferent substances are concurrently vaporized from differentevaporation sources.

Next, PCzPA was deposited to a thickness of 10 nm by evaporation to formthe hole-transport layer 912.

Next, the light-emitting layer 913 was formed on the hole-transportlayer 912. In the case of the light-emitting element 4,7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA) and 1,6BnfAPrn-03 were deposited byco-evaporation with a mass ratio of cgDBCzPA to 1,6BnfAPrn-03 of 1:0.01.The thickness of the light-emitting layer 913 was 25 nm.

Next, on the light-emitting layer 913, cgDBCzPA was deposited byevaporation to a thickness of 10 nm and then bathophenanthroline(abbreviation: Bphen) was deposited by evaporation to a thickness of 15nm to form the electron-transport layer 914. Furthermore, lithiumfluoride was deposited by evaporation to a thickness of 1 nm on theelectron-transport layer 914 to form the electron-injection layer 915.

Finally, aluminum was deposited by evaporation to a thickness of 200 nmon the electron-injection layer 915 to form a second electrode 903serving as a cathode. Thus, the light-emitting element 4 was obtained.Note that, in all the above evaporation steps, evaporation was performedby a resistance-heating method.

Table 5 shows an element structure of the light-emitting element 4obtained in the above-described manner.

TABLE 5 Hole- Hole- Light- Electron- First injection transport emittingElectron-transport injection Second electrode layer layer layer layerlayer electrode Light- ITSO PCzPA: PCzPA cgDBCzPA: cgDBCzPA Bphen LiF Alemitting (110 nm) MoOx (10 nm) 1,6BnfAPrn-03 (10 nm) (15 nm) (1 nm) (200nm) element 4 (4:2 50 nm) (1:0.01 25 nm)

The fabricated light-emitting element 1 was sealed in a glove boxcontaining a nitrogen atmosphere so as not to be exposed to the air(specifically, a sealant was applied onto outer edges of the elements,and at the time of sealing, UV treatment was performed first and thenheat treatment was performed at 80° C. for 1 hour).

<<Operation Characteristics of Light-Emitting Element 4>>

Operation characteristics of the fabricated light-emitting element 4were measured. Note that the measurement was carried out at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 28 shows voltage-luminance characteristics of the light-emittingelement 4. In FIG. 28, the vertical axis represents luminance (cd/m²)and the horizontal axis represents voltage (V). FIG. 29 showsluminance-current efficiency characteristics of the light-emittingelement 4. In FIG. 29, the vertical axis represents current efficiency(cd/A) and the horizontal axis represents luminance (cd/m²). FIG. 30shows voltage-current characteristics of the light-emitting element 4.In FIG. 30, the vertical axis represents current (mA) and the horizontalaxis represents voltage (V). FIG. 31 shows current density-luminancecharacteristics of the light-emitting element 4. In FIG. 31 the verticalaxis represents luminance (cd/m²) and the horizontal axis representscurrent density (mA/cm²).

FIG. 29 revealed that the light-emitting element 4 including1,6BnfAPrn-03 that is the organic compound of one embodiment of thepresent invention was a highly efficient element. Table 6 shows initialvalues of main characteristics of the light-emitting element 4.

TABLE 6 Current Current Power External Voltage Current densityChromaticity Luminance efficiency efficiency quantum (V) (mA) (mA/cm²)(x, y) (cd/m²) (cd/A) (lm/W) efficiency (%) Light- 3.0 0.7 17 (0.14,0.09) 960 5.5 5.8 6.9 emitting element 4

The above results revealed that the light-emitting element 4 fabricatedin this example had high current efficiency.

FIG. 32 shows an emission spectrum of the light-emitting element 4 thatwas obtained when current was applied to the light-emitting element 1 ata current density of 25 mA/cm². As shown in FIG. 32, the emissionspectrum of the light-emitting element 4 had a peak at around 454 nm,which indicates that the peak was derived from emission of 1,6BnfAPrn-03that is the organic compound of one embodiment of the present invention.

The light-emitting element 4 was subjected to a reliability test.Results of the reliability tests are shown in FIG. 33. In FIG. 33, thevertical axis represents normalized luminance (%) with an initialluminance of 100% and the horizontal axis represents driving time (h) ofthe element. Note that in the reliability test, the light-emittingelement 4 was driven under the conditions where the initial luminancewas set to 5000 cd/m² and the current density was constant. The resultsdemonstrated that the luminance of the light-emitting element 4 after100-hour driving was approximately 88% of the initial luminance. Thus,the comparative light-emitting element 3 including the organic compoundof one embodiment of the present invention had not only high colorpurity but also a long lifetime. The above results indicate that the useof 1,6BnfAPrn-03, the organic compound that is one embodiment of thepresent invention and has a structure in whichbenzo[b]naphtho[1,2-d]furan is bonded to 1,6-diaminopyrene, enables alight-emitting element that emits blue light with high color purity andhas a long lifetime to be provided.

Thus, the use of the organic compound of one embodiment of the presentinvention enables a light-emitting element that has high efficiency anda long lifetime to be obtained. In addition, 1,6BnfAPrn-03 has astructure in which a phenyl group is bonded to the 6-position ofbenzo[b]naphtho[1,2-d]furan; thus, an element that had very high colorpurity, high efficiency, and high reliability was obtained. Thisrevealed that among the compounds in the present invention, the compoundhaving the structure in which a substituted or unsubstituted phenylgroup, particularly, an unsubstituted phenyl group is bonded to the6-position of benzo[b]naphtho[1,2-d]furan is preferable.

REFERENCE NUMERALS

101: first electrode, 102: EL layer, 103: second electrode, 111:hole-injection layer, 112: hole-transport layer, 113: light-emittinglayer, 114: electron-transport layer, 115: electron-injection layer,116: charge-generation layer, 201: first electrode, 202(1): first ELlayer, 202(2): second EL layer, 202(n−1): (n−1)th EL layer, 202(n): n-thEL layer, 204: second electrode, 205: charge-generation layer (I),205(1): first charge-generation layer (I), 205(2): secondcharge-generation layer (I), 205(n−2): (n−2)th charge-generation layer(I), 205(n−1): (n−1)th charge-generation layer (I), 301: elementsubstrate, 302: pixel portion, 303: driver circuit portion (source linedriver circuit), 304 a, 304 b: driver circuit portion (gate line drivercircuit), 305: sealant, 306: sealing substrate, 307: wiring, 308:flexible printed circuit (FPC), 309: n-channel FET, 310: p-channel FET,311: switching FET, 312: current control FET, 313: first electrode(anode), 314: insulator, 315: EL layer, 316: second electrode (cathode),317: light-emitting element, 318: space, 7100: television device, 7101:housing, 7103: display portion, 7105: stand, 7107: display portion,7109: operation key, 7110: remote controller, 7201: main body, 7202:housing, 7203: display portion, 7204: keyboard, 7205: externalconnection port, 7206: pointing device, 7302: housing, 7304: displaypanel, 7305: icon, 7306: icon, 7311: operation button, 7312: operationbutton, 7313: connection terminal, 7321: band, 7322: clasp, 7400: mobilephone, 7401: housing, 7402: display portion, 7403: operation button,7404: external connection port, 7405: speaker, 7406: microphone, 900:substrate, 901: first substrate, 902: EL layer, 903: second electrode,911: hole-injection layer, 912: hole-transport layer, 913:light-emitting layer, 914: electron-transport layer, 915:electron-injection layer, 8001: lighting device, 8002: lighting device,8003: lighting device, and 8004: lighting device.

This application is based on Japanese Patent Application serial no.2013-155318 filed with the Japan Patent Office on Jul. 26, 2013, theentire contents of which are hereby incorporated by reference.

The invention claimed is:
 1. An organic compound represented by GeneralFormula (G1):

wherein: Ar¹ and Ar² separately represent a substituted or unsubstitutedaryl group having 6 to 13 carbon atoms forming a ring; R¹ to R⁸separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms,and a substituted or unsubstituted aryl group having 6 to 10 carbonatoms; and X¹ and X² separately represent a substituted or unsubstitutedbenzo[b]naphtho[1,2-d]furanyl group.
 2. The organic compound accordingto claim 1, wherein nitrogen atoms in General Formula (G1) areseparately bonded to the 6-position or the 8-position of thebenzo[b]naphtho[1,2-d]furanyl group.
 3. An organic compound representedby General Formula (G2):

wherein: Ar¹ and Ar² separately represent a substituted or unsubstitutedaryl group having 6 to 13 carbon atoms forming a ring; and R¹ to R¹⁷ andR¹⁹ to R²⁷ separately represent any one of hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 6 carbon atoms, a cyano group,halogen, a substituted or unsubstituted haloalkyl group having 1 to 6carbon atoms, and a substituted or unsubstituted aryl group having 6 to10 carbon atoms.
 4. The organic compound according to claim 3, whereinthe substituted or unsubstituted aryl group having 6 to 13 carbon atomsand the substituted or unsubstituted aryl group having 6 to 10 carbonatoms separately represent any one of a phenyl group, a 1-naphthylgroup, a 2-naphthyl group, an ortho-tolyl group, a meta-tolyl group, apara-tolyl group, an ortho-biphenyl group, a meta-biphenyl group, apara-biphenyl group, a 9,9-dimethyl-9H-fluoren-2-yl group, a9,9-diphenyl-9H-fluoren-2-yl group, a 9H-fluoren-2-yl group, apara-tert-butylphenyl group, and a mesityl group.
 5. The organiccompound according to claim 3, wherein the substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms represents any one of a methylgroup, an ethyl group, an n-propyl group, an isopropyl group, a n-butylgroup, a sec-butyl group, an isobutyl group, a tert-butyl group, ann-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentylgroup, a neopentyl group, an n-hexyl group, an isohexyl group, asec-hexyl group, a tert-hexyl group, a neo-hexyl group, a cyclohexylgroup, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutylgroup, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group, andwherein the substituted or unsubstituted alkoxy group having 1 to 6carbon atoms represents any one of a methoxy group, an ethoxy group, ann-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxygroup, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, anisopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, aneo-pentyloxy group, an n-hexyloxy group, an isohexyloxy group, asec-hexyloxy group, a tert-hexyloxy group, a neo-hexyloxy group, acyclohexyloxy group, a 3-methylpentyloxy group, a 2-methylpentyloxygroup, a 2-ethylbutoxy group, a 1,2-dimethylbutoxy group, and a2,3-dimethylbutoxy group.
 6. The organic compound according to claim 3,wherein the organic compound is represented by General Formula (G4):

wherein R²⁹ to R³⁸ separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, and a substituted or unsubstituted arylgroup having 6 to 10 carbon atoms.
 7. The organic compound according toclaim 3, wherein the organic compound is represented by StructuralFormula (100):


8. A light-emitting element comprising the organic compound according toclaim
 3. 9. A light-emitting device comprising the light-emittingelement according to claim
 8. 10. An electronic appliance comprising thelight-emitting device according to claim
 9. 11. A lighting devicecomprising the light-emitting device according to claim
 9. 12. Anorganic compound represented by General Formula (G3):

wherein: Ar¹ and Ar² separately represent a substituted or unsubstitutedaryl group having 6 to 13 carbon atoms forming a ring; and R¹ to R⁸, R¹⁰to R¹⁸, and R²⁰ to R²⁸ separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, and a substituted or unsubstituted arylgroup having 6 to 10 carbon atoms.
 13. The organic compound according toclaim 12, wherein the substituted or unsubstituted aryl group having 6to 13 carbon atoms and the substituted or unsubstituted aryl grouphaving 6 to 10 carbon atoms separately represent any one of a phenylgroup, a 1-naphthyl group, a 2-naphthyl group, an ortho-tolyl group, ameta-tolyl group, a para-tolyl group, an ortho-biphenyl group, ameta-biphenyl group, a para-biphenyl group, a9,9-dimethyl-9H-fluoren-2-yl group, a 9,9-diphenyl-9H-fluoren-2-ylgroup, a 9H-fluoren-2-yl group, a para-tert-butylphenyl group, and amesityl group.
 14. The organic compound according to claim 12, whereinthe substituted or unsubstituted alkyl group having 1 to 6 carbon atomsrepresents any one of a methyl group, an ethyl group, an n-propyl group,an isopropyl group, a n-butyl group, a sec-butyl group, an isobutylgroup, a tert-butyl group, an n-pentyl group, an isopentyl group, asec-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexylgroup, an isohexyl group, a sec-hexyl group, a tert-hexyl group, aneo-hexyl group, a cyclohexyl group, a 3-methylpentyl group, a2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group,and a 2,3-dimethylbutyl group, and wherein the substituted orunsubstituted alkoxy group having 1 to 6 carbon atoms represents any oneof a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxygroup, an n-butoxy group, a sec-butoxy group, an isobutoxy group, atert-butoxy group, an n-pentyloxy group, an isopentyloxy group, asec-pentyloxy group, a tert-pentyloxy group, a neo-pentyloxy group, ann-hexyloxy group, an isohexyloxy group, a sec-hexyloxy group, atert-hexyloxy group, a neo-hexyloxy group, a cyclohexyloxy group, a3-methylpentyloxy group, a 2-methylpentyloxy group, a 2-ethylbutoxygroup, a 1,2-dimethylbutoxy group, and a 2,3-dimethylbutoxy group. 15.The organic compound according to claim 12, wherein the organic compoundis represented by General Formula (G5):

wherein R²⁹ to R³⁸ separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, and a substituted or unsubstituted arylgroup having 6 to 10 carbon atoms.
 16. The organic compound according toclaim 12, wherein the organic compound is represented by StructuralFormula (101):


17. A light-emitting element comprising the organic compound accordingto claim
 12. 18. A light-emitting device comprising the light-emittingelement according to claim
 17. 19. An electronic appliance comprisingthe light-emitting device according to claim
 18. 20. A lighting devicecomprising the light-emitting device according to claim 18.